Chemistry, Chemical Reagents, Physics, and the History of Manuscripts
Please Note: This is not a complete article on how the physical sciences can be used to help us in textual criticism. This is an extremely broad field, with references scattered in journals of many fields and (as far as I know) no general manual. I have pulled material together from a lot of sources, but this is just a collection of notes, not a comprehensive summary of the field.
Sections: Chemical Reagents * Paints and Pigments * Carbon Dating * Spectroscopy * Isotope Analysis * DNA Sequencing * Detecting Forged Manuscripts
Chemical Reagents
Old manuscripts can be extremely difficult to read. The most obvious examples are palimpsests, but even a manuscript's upper writing can fade.
Today, scholars have excellent tools for dealing with such problems (notably ultraviolet photography, though there are many other techniques in use). That wasn't so in the past, but the desire to read the manuscripts was just as great. In consequence, scientists developed a number of chemicals for trying to bring out faded or eradicated ink. The first ink restorer seems to have been oakgall (gallic acid or, technically, trihydroxybenzoic acid, C6H2(OH)3COOH), used as early as the early seventeenth century (possibly earlier) -- ironic, since oakgall was also used to make iron-gall inks. It was of limited use, but much stronger chemicals were eventually discovered. Some of the reagents used in the nineteenth century include ammonic sulphydrate, potassium nitrate, potassium bisulfate, and Gioberti tincture -- successive coats of hydrochloric acid and potassium cyanide (!).
Supposedly (according to E. Maunde Thompson's An Introduction to Greek and Latin Paleography, p. 65), the "most harmless [reagent] is probably hydro-sulphuret of ammonia." Similarly, M. R. James wrote that "ammonium bisulphide... unlike the old-fashioned galls, does not stain the page." Which mostly tells you how damaging the others are. Hydro-sulphuret of ammonia is a strong hair dye, with acid properties (it also smells terrible and is banned for many uses because it's so dangerous). It is certainly capable of damaging manuscripts.
If you somehow talk someone into letting you use this gunk on an old manuscript, be sure to dab or pat it onto the parchment. Do not paint it (which can cause the ink to smear) or spray it (which will apply more than you need). At least one very important manuscript, Cambridge, University Library, MS. Ff.5.48, containing the unique copy of the ancient ballad romance "Robin Hood and the Monk," has been rendered almost unreadable by some vandal who painted it with an ink restorer.
The problem with these chemicals is that, although they can bring out the writing in the short term, they destroy the manuscript in the slightly longer term. They can cause the ink to blot and the parchment to decay. (As a result, there was a brief period during which scholars applied their glop, photographed the results, and washed the chemicals off. Somehow this doesn't seem much better than leaving it on the manuscripts.) Among New Testament manuscripts, this sort of defacement happened notably to C (though it is not clear whether Tischendorf, who is frequently blamed for it, was guilty; other scholars seem to have been the primary culprits). The problem is especially bad when multiple chemicals are applied -- as was done, e.g., to the manuscript of The Poem of the Cid); not only does this damage the parchment, but it also renders ultraviolet photography less effective. Ian Michaels, in his introduction to the Penguin bilingual edition The Poem of the Cid, tells us on p. 15 that "the reagents have not only blackened the folios where they were applied but also appear to have eaten through the parchment in the worst affected places; they have also left a flourescence which greatly reduces the effectiveness of ultra-violet light." The chemicals used were apparently ammonic sulphydrate plus, in a few cases, "yellow potassium prussiate" and hydrochloric acid.
Chemical "enhancement" of manuscripts is now strongly frowned upon, and has effectively stopped -- having been replaced by much less damaging techniques. Unfortunately, there are instances of the use of chemicals as late as the 1920s; many manuscripts which survived the Middle Ages have now been permanently damaged by more modern scholars who generally did not learn much as a result of their vandalism.
It's interesting to note that some of these chemical reagents were known long ago. Pliny the Elder was perhaps the first to describe an invisible ink. Of greater significance, perhaps, is a remark by Philo of Byzantium, who refers to an ink of nutgalls which could be developed with what we would now call copper sulfate. Since many ancient inks contained nutgall, Philo deserves credit, in a sense, for the first method of "developing" palimpsests.
Paints and Pigments
Chemistry can be a powerful tool for textual criticism in its paleographic aspects -- specifically dating and verification of manuscripts. Spectroscopy and other tests can reveal chemicals contained in inks or paintings without damaging the manuscript. And if a manuscript contains a chemical not in use at the time it was thought to have been written, well, that implies a problem. This line of argument has been used, e.g. to implicate 2427 as a forgery, since it probably contains Prussian Blue, a dye not invented until the eighteenth century, well after 2427's alleged date. The problem with such arguments is that they depend to a strong extent on our knowledge of history of chemical use; there is currently a major argument about another chemical, titanium dioxide, thought to be modern but now found in small amounts in ancient inks.
(Incidentally, while Prussian Blue is the most famous, and most easily detected, of modern colours used to fake artifacts, it is not the only one. The infamous Piltdown Man hoax of the early twentieth century involved bones of a human being and an orangutan being jumbled together, broken up, filed -- and stained to make them look like a match. Some of the staining was done with a commercial paint, Vandyke Brown. Vandyke Brown is not as chemically unique as Prussian Blue, but it will surely be evident that million-year-old fossils didn't go around staining their teeth with paint manufactured around the beginning of the twentieth century! -- nor even with cassel earth, a sort of peat, which gave Vandyke himself the color.)
Another recent surprise came when a technique called Raman spectroscopy was used on the British Library's King George III copy of the Gutenberg Bible. According to a (non-technical) article in Renaissance magazine (issue #45, p. 18), the inks used to illuminate that printed book (which of course is contemporary with some late manuscripts) included cinnabar for bright red (as expected), carbon for black, azurite for blue (not a surprise, though some blues use lapis lazuli), calcium carbonate (chalk) for white, malachite for olive green, and verdigris (copper ethanoate) for dark green. Those were no surprise. More notably, the Göttingen copy was found to contain anatase and rutile, which had been regarded as modern compounds. This may be the result of contamination, but it may be a hint that we may still have more to learn about ancient inks.
Some pigments can be detected simply by the way they decay over time. An example is paint using white lead. White lead was prepared by exposing elemental lead to the fumes of vinegar (acetic acid) to create lead acetate (also called lead (II) ethanoate, Pb(CH3COO)2) and sundry hydrates. Often the work was done in the presence of animal dung to make more carbon dioxide available and speed the reaction.
Lead white was a delicate white, much liked both for a wall covering and for detailed paint. Often it was mixed with other pigments to produce pale shades such as pink. Sadly, it is unlikely to look pink any more. If exposed to hydrogen sulfide (a common by-product of gas lighting and especially of coal-burning), it reacts to form lead sulfide (PbS), which is black. The decay of white lead has been known for centuries (Cennino mentioned it in the early fifteenth century), but it was such an excellent white that it continued to be used -- there was no good alternative until zinc white was discovered after the manuscript era, and there was no good and cheap alternative until titanium white came along in the early twentieth century. So if you see a painting of someone's face which looks as if it had been expected to be pink, but now looks dark brown or black, odds are that it used white lead. Unfortunately, the use of white lead isn't very useful as a dating method; its preparation was first described by Theophrastus (372-286 B.C.E.), and it was widely used by the Romans. (Information in this paragraph primarily from John Emsley, Nature's Building Blocks: An A-Z Guide to the Elements, corrected edition, Oxford, 2003). It was still being used as a pigment as late as the time of England's Queen Elizabeth I (died 1603); her extremely heavy makeup was said to be founded upon white lead. (I can't help but wonder if it shortened her life.)
Speaking of pigments and makeup (keep in mind that most manuscripts with illuminations were painted before the invention of oil paints), the best of the natural oil bases, linseed oil, was known from the eighth century but reportedly was not used for painting until the fifteenth, in part because it took a long time to figure out how to fully purify it (the best method of preparing linseed oil was distillation, but distillation was not applied to oils for many centuries). And even linseed oil turns yellow over time; poppyseed oil replaced it, but not until long after the manuscript era. Also after the manuscript era was the practice of adding parafins or fats to paints, so that every paint had the same texture; until then, different pigments had different physical properties such as granularity. Oil paints seem to have been originally used for large-scale decoration; only later were they adapted for painting -- Leonardo da Vinci was one of the first to use them; some of his teachers still used tempera. Paints before the introduction of oils were almost like wet versions of pancake makeup, using materials such as egg white or fish glue to attach the pigments to the page. This affected how they were laid down, how they were mixed, and how they survived. Many illuminated manuscripts seem to be in a rather un-modern style. But this may have had more to do with the paint than the painter.
Oil, tempera, glair, and other products used to suspend pigments are known as "binders." Most binders are also responsible for adherence -- that is, they cause the pigment to stick to the surface of the page. But these are separate functions, and there are instances where they are separate -- for example, gold leaf was its own binder but needed a separate sticky substance, such as honey or gesso, to cause it to stick to the page.
Most adherent compounds needed to be applied while still fresh. Whereas a watercolor paint could be renewed by adding water, you could not add extra tempera or glair to a paint without changing its color and composition. So paint had to be made and applied quickly, before it began to dry out.
It's worth keeping in mind that the different pigments needed to be used with oils than with other binders. Oil has a different index of refraction than the others, meaning that colors actually changed when mixed with oil rather than tempera or glair. Ultramarine in oil is darker and less attractive, verdigris loses some of its opacity. On the other hand, the so-called "lake" colors, which aren't worth much in the older binders, gained in vibrancy with oil. (Lakes were, in effect, what you got when you mixed an opaque material such as calcite with a dye or pigment. In other words, you dyed the calcite. This wouldn't be very effective with an opaque binder but would work better with oils. The Romans seem to have known of lakes, but the knowledge doesn't seem to have been preserved into the Middle Ages.) Again, though, this is not likely to matter in a Biblical illuminated manuscript.
Also, while NT scholars don't have to deal with dyes very often, it's worth keeping in mind that different dyes worked with different fabrics. Parchment is an animal product, as are cloths such as wool and silk, and the dyes used on parchment typically adhered to a protein. Papyrus and paper are plant products, as are such fabrics as linen, and the dyes used on them typically adhered to cellulose. So dyes which worked on the one might not work on the other -- for instance, although madder was long used to dye wool red, it wasn't until the mid-eighteenth century that anyone figured out a way to dye cotton red. Also, pigments generally required nothing except a binder to adhere to a page; dyes often required a mordant (alum was a common one, and one around which a very large industry was eventually built -- note how many of the entries below involve alum. Also note that there were several compounds called "alum," with different properties.)
Table of Common Chemicals Used in Ancient Inks and Pigments
Please note: This list isn't even close to complete; I'm adding chemicals as I learn of them. Also, this table needs a long preface.
To begin with, although I don't lest them in the table below, we should probably mention the two most common components in ancient paints: Egg white and egg yolk. These were not used for color; rather, they were binders, holding the pigment to the page. Egg white is usually refered to as "glair"; egg yolk was used to make tempera paint. (The name "tempera" being derived from the verb temperare, "to temper," since the tempering agents served both to bind the paint and sometimes to change its appearance. They also affected the transparency of the pigment -- how much the background showed through.) Both binding agents were common, tempera probably more so, although the exact recipe used to make tempera from egg yolk changed over the centuries. In general the pigments were ground into a fine powder, then dissolved in a small quantity of water, which was then mixed with the egg yolk. Once the yolk fully dried, it proved quite stable; even water affected it only slightly. Yolk contains enough oil to be rather like oil paint, except rather duller and less reflective. (Tempera in fact is said to retain its color and stability better than pigments in oil, except for the problem that it hardens to be more fragile than oil and so is more subject to damage such as cracks and flaking.)
Glair does not mix readily with water, and had to be whipped to reach the proper texture -- and this had to be done in a special container to prevent contamination of either the glair or the container. Interestingly, scribes found that adding a little ear wax made glair easier to prepare and work with. (Just what you wanted to know, right?)
If someone ever invents an easy test for egg yolk, it will be a good way of checking for forgeries; starting in the fifteenth century, it was gradually replaced by oil bases, with egg no longer in use in the sixteenth century and after.
Although both glair and tempera were used in manuscripts, Daniel V. Thompson, The Materials and Techniques of Medieval Painting, tells us that of the various binders, "glair and gum [were] chiefly for books, egg yolk chiefly for panels, lime chiefly for walls [in whitewash], and size and oil for woodwork."
In later centuries, gum arabic (acacia gum, a complex compound, also known as mastic) came to be used as a binder as well, either in mixture with or as a substitute for glair or tempera. It also had the useful effect of preventing clumping of pigments in inks. This made it a key ingredient in "watercolor" drawings. Properly, gum arabic was made from acacia plants -- although sometimes the gums of other sorts of trees were used. From what I can tell, though, this was rare in New Testament manuscripts; watercolors tend to be applied in broad strokes and with pale colors that simply aren't suitable for small illuminations!
Gum arabic may actually have been more useful in inks; it was used by the Egyptians because of its ability lampblack from clumping. In the Renaissance, it was also used, along with turpentine, linseed oil, and white lead or lime to prepare wood for use in panel paintings. They would also use size or gesso.
Tannin was also common in inks, as an acidic fixative (that is, it ate into the surface of the writing material, making the ink stick better). Most tannin probably came from oakgall ink, but apparently tannin was sometimes used on its own. (It was also used as a dye -- but, since it produced a yellow-brown color, it probably wasn't very popular with the wealthy. Its main virtue was that it was color-fast.)
More common as a binder was size, or (as we now call it) gelatin. This was made from skin and other body parts of dead animals, and probably contained other materials as well. It was especially useful for binding blue pigments, most of which did not work well with tempera (when a binder other than tempera was used, the result was often called a "distemper"). Size-based glues were also good for binding gold leaf. (Properly speaking, "size" can refer to many materials; the name means "seat," because size was used to seat, i.e. to hold, materials in place. In some contexts, it was used to slightly raise the pigment above the levels of those around it. For these purposes, any material, such as plaster, could be a size, but the best were things like gelatin or gelatin with honey. Sadly for the noses of scribes, size was stickiest and most useful when it had been allowed to rot before application.
Size was also used to coat paper to make it hold ink better -- an important point in detecting forgeries, because if a modern forger uses old paper to try to avoid being caught by radiocarbon dating, the size may well have come off the paper, causing the ink to spread out more. Blotty, runny ink can thus be an indication of a forgery, although it's not proof because there were of course papers that weren't very well sized in the first place.
The choice of binders was very important. Western artists apparently used good binders, and their illuminated manuscripts have fared relatively well. Byzantine artists, on the other hand, seem to have settled on very poor binders, with the result that the miniatures in their illuminated texts are often badly flaked and abraded.
In the far east, it was not rare to add spices such as cloves or musk or honey to ink, just to make it smell good. I have not heard of this being done in the west. In the case of honey, it would also produce a better ink -- the sugars in the honey, like gum arabic in Egyptian ink, would keep the ink from clumping (gum arabic is mostly sugars).
It's worth noting that different regions had relatively standard palettes of pigments, meaning that you can sometimes use the colors in a manuscript to identify where it came from -- e.g. early British manuscripts tended to use a palette of red (from red lead), yellow (from orpiment), and green (from verdigris), without a blue or purple color. Pliny the elder asserted that classical Greek painters used only four colors, black, white red, and yellow (so Philip Ball, Bright Earth, p. 15), although we cannot verify this and do not know which actual pigments were used; Ball points out that 29 different pigments have been found in use at Pompeii.
Ball, p. 68, hints that the four-color palette might be by analogy to the four alleged elements of earth, air, fire, and water. In The Elements: A Very Short Introduction, he says that the Athenian Antiochos explicitly linked white to water, black to earth, red to air, and water to Fire; that Leon Battista Alberti made fire red, air blue, water green, and earth cinder-colored; and that Leonardo da Vinci accepted the first three of these but made earth yellow. This may have tied in with Galen's theory of humours: red blood, white phlegm, black bile, yellow bile. (In assessing these odd lists, we should keep in mind that the modern color theory of red/green/blue had not even been imagined.)
And while some schools of art liked to use limited palettes (which, if nothing else, reduced the problems of chemical mixture), this was by no means universal. The famous Ellesmere Manuscript of Chaucer's Canterbury Tales, for instance, uses lapis lazuli for blue, both in pure form and with a white (chalk?) mixture; red lead for orange-red; chalk white; carbon black, a green that is probably copper-based; an organic red (kermes, madder, or orchil) for purple-red; turnsole for a more transparent purple-red; a few instances of orpiment or some other yellow; a brown ink, and gold.
Also, in many schools of art, it was considered improper to mix colors -- perhaps because mixed colors were less bright than pure colors; also, of course, the colors might react with each other. Furthermore, the ancients did not have anything resembling color theory; it wasn't until the seventeenth century that Newton produced a color theory of light, and the idea of complimentary colors and the color wheel is a nineteenth century invention. Lacking these, mixing colors would inherently have been a hit-or-miss process -- not even a recipe for combining particular tints was much help when certain color words could refer to hues as diverse as yellow and blue! It was not until the invention of oil painting that mixing colors became commonly accepted. The lack of ability to produce intermediate shades of course limited the level of detail possible, but it does mean that many manuscript illustrations were particularly bright and striking.
When we do see color detail in a manuscript illustration, it may be the result of color overlays. So, for instance, the manuscript 2400 has dozens of illustrations where colors went on in three layers: a thin primer, then thick basic colors, then, in a few places, a second color was placed in thin layers over the first to add detail. The results of this don't look very attractive to me, but I'm no artist -- and, in any case, that's a comment on the painter, not the way in which the painter worked.
To be sure, color mixing did sometimes happen, even in the same school of art; there were cultural factors involved. In ancient Egypt, for instance, it was considered permissible to mix colors in secular art, but religious art used only pure colors.
Also, although it doesn't matter to us, it's worth noting that pure colors will look the same whatever sort of sensor observes them, because they emit a certain spectrum of light, always. This will not necessarily be true of mixed colors, which depend on the way the human eye senses colors -- to us, for example, because yellow light activates both the green and red sensors in our eyes, you can imitate a yellow light by producing red and green light. This won't necessarily work for, say, most birds, which have different light sensors; to them, green plus red light looks like green plus red! So if a non-human species ever observes a painting done with mixed pigments, it might not look the way it does to us.
Note: There are so many colors in this table that I've put together an index by basic colors, below. In this list, the capitalized word is the name under which it alphabetizes, e.g. "green Ochre" is filed under Ochre; "Naples yellow" files under Naples.
| Color | Pigments | |
| black | Bone black, Lampblack, Wine Black | |
| blue | Azurite, Egyptian Blue, Indigo, Lapis lazuli, Turnsole | |
| brown | Bistre, Sepia | |
| gold | Gold | |
| green | Buckthorn, Chrysocolla, Green earth, Honeysuckle green, Iris green, Jade, Malachite, Mixed green, Nightshade green, green Ochre, Sap green, Verdigris | |
| orange | Bistre, Realgar | |
| purple | Archil, Dragon's blood, Turnsole, Tyrian purple (note that the Greek πορφυρεος and Latin porphyria or purpure do not refer specifically to a violet color but to any dark red or violet or even to blues; drying blood, e.g., was purple, so when something is called purple in an ancient text, it is not a definite description of color.) | |
| red | Cinnabar, Dragon's blood, Dyewoods, Hematite, Kermes, red Lead, (red) Madder, red Ochre, Realgar, Whelk red | |
| silver | Silver, Tin | |
| white | Bone white, Calcite, (Gesso), white Lead, Shell white, Silver | |
| yellow | Aloe, Bile yellow, Buckthorn, Celandine, Gold, Indian yellow, yellow Lead, Mosaic gold, Naples yellow, yellow Ochre, Orpiment, Saffron, Weld |
The color wheel below probably isn't very accurate on your monitor, but it will give you some idea of the relative colors of some ancient pigments.
Table of Pigments
| Common Name | Chemical Formula | Color | Comments | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Alkanet | complex organic | red | Pliny reported the Egyptians made a red dye from Alkanet root. I know of no uses in manuscripts, although the dye was still used in the Middle Ages. It was not very color-fast. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Aloe | complex organic | yellow | Seemingly not used as an ink or dye in itself, but it could be mixed with something else to give a yellow color -- e.g. it might be mixed with egg yolk and a metal (mercury, silver, tin) to give the impression of gold. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Archil | complex organic | purple | A purple color derived from a lichen. The name comes from Latin rocella, the name for the lichen, via oricella and older English orchil. It was used primarily as a dye rather than as a pigment. Also spelled orchell or variants (e.g. orchein), as well as cudbear, and sometimes confused with Turnsole. Like many organic dyes, to convert the raw lichen to a usable dye required exposing it to ammonia (among other chemicals), which in practice meant stale urine. It wasn't known in the west until relatively late in the manuscript era, and was often hard to obtain in any case because the lichen supply was limited. And it was synthesized relatively early in the modern era, so there is a good chance that if archil does turn up in a manuscript, it's a forgery. Pliny claimed the Egyptians used it as a dye. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Azurite | Cu(CO3)2(OH)2 Hydrous copper carbonate | Blue | Often found with malachite; the two are close chemical relatives. (When they were created first artificially, the workers had trouble getting consistent color results; it turns out that which compound the reaction produced depended on the temperature.) A very hard mineral, which required much grinding before it could be used as a pigment (and which, even when ground, retains its crystalline structure). It also tended to be found as medium-sized grains in a matrix of sand, malachite, and other compounds. This meant that it had to be prepared by grinding and then separating with water, soap, and other chemicals. The result was a very deep blue if the grains were the right size, but a paler color if they were ground too small. (Grinding always affects the hue of a crystaline pigment, because the shape of the surface affects reflections, but this was more noticeable with azurite, perhaps because it was so hard to grind. There are actually paintings which use azurite for two different colors by changing the way it was ground.) The large particle size meant that it often needed a different binder (size rather than tempera), and it had to be laid on in thick layers -- a difficult technical challenge, and one that meant that varnish did not mix well with azurite. Also, it could easily chip off. And those large grains meant that varnish could affect it and cause it to discolor. It might also darken if exposed to sulfur or acids, or undergo a chemical change to malachite, making the blue turn green. Because it is so difficult to prepare, it quickly went out of use when modern blues became available (the fact that available supplies were becoming exhausted may also have played a role, or just the fact that it didn't work especially well in oil paints). Moderns may also find it listed as "blue bice" or "blue verditer"; this too is copper carbonate, but prepared chemically rather than from natural deposits. A truly pure azurite will be a very deep blue, but because it is often mixed with malachite, it is likely to look blue-green. Indeed, in early times the mixed material was sometimes called "verde azzurro," "blue-green," or "acquamarine" because it was used to create sea colors. Like green copper compounds, it was sometimes mixed with pine resin or bitumen to increase its chemical stability. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Bile Yellow | complex organic | yellow | Made from the gallbladders of various vertebrates, with fish being the most preferred; tortoises were also a common source. It was ground with chalk or vinegar or other compounds. It was used for golden shades, primarily in Greek regions. (Oxgalls were also used for a yellow color which was related to the color known, oddly, as "Dutch Pink," but this seems to have been after the manuscript era.) | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Bistre | complex organic | orange or brown | Made by burning the roots of certain resinous trees, mostly beeches. It is not a very stable color, so it probably was not often used, but because it was not developed until the fourteenth century, it can be used to date such manuscripts as do use it. However, it might also be a sign of a forgery, because it was much more widely used in the eighteenth century than before (or after). | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Bole | (varies?) | Pink and others | A pink clay, commonly said to be from Armenia but apparently found in many places, described as "soapy," so it was not a good pigment in itself. It was, however, a good substance to mix with size to give the size a color. Pink bole was apparently the most popular, but there were red, yellow, green, and white boles; the term "bole" refers to the texture, not the color. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Bone Black | complex organic | Black | Lampblack was probably the best
black available to the ancients, since it was almost pure black carbon, and hence
very black plus the particles were very small and made a good even ink.
But unless one was willing to burn candles or oil solely to produce ink, the supply
was limited. Among the substitutes sometimes used was bone black -- charred bone.
Although this contained only about 10%-20% carbon, with most of the rest being calcium
phospate plus a few percent of calcium carbonate and other things, it was a very good
black if properly prepared. However, it was trickier than lampblack because the bone
had to be very finely ground to be usable, and heated very carefully to prevent it
burning away. Typically it was more of a brown than a black color as a result (this usually was the result of impurities; this browner version was sometimes referred to as "bone brown."). It was not used in frescoes or mortars, because it was efflorescent.
There are stories of human bones being used to make bone black. I know of no verified evidence for this, but it is certainly possible. The only question is, why would anyone do it when other bones were available? Certainly such ink would not have been used by, e.g., Jews. Ivory is also said to have been used. This strikes me as a prestige item, since it had only slightly more carbon than regular bone black, but it would sound fancier. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Bone White | complex organic | White | Although white lead was the preferred pure white in ancient paintings, it did not mix well with some colors. When a mixed color was needed, bone white might be used. The bones were heated to a high temperature in a fire, until they turned white, and then ground. It was not easy to work with because it was pasty, but it was combined with verdigris or orpiment to produce stable mixes of those colors. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Brass | Cu + Zn (copper plus zinc) | Yellow metallic | Brass was sometimes powdered to create a bronze color in paintings. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Buckthorn | complex organic | Yellow or Green; also black | The juice of unripe buckthorn was very occasionally used as a yellow ink, or mixed with a blue to produce a green color. Pliny said the Egyptians used buckthorn as a dye. However, the color was very unstable, so it was rarely used in manuscripts and, as far as we know, not at all in other sorts of paintings. Riper buckthorn might be used to produce a Sap Green (which see). Buckthorn bark was also used to make a black ink, but this seems to have been fairly rare (and extremely complex to make) -- and the buckthorn was usually mixed with iron anyway, so it's not clear how much it contributed to the color.
Buckthorn berries were used for a time to make a pink color (known as Dutch Pink or English Pink or stil-de-grain), but this faded quicky and probably was never used in a manuscript. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Calcite | CaCO3 Calcium Carbonate | usually white | Calcium carbonate occurs in a wide variety of forms. There are three crystal forms (calcite, aragonite, and vaterite, though the last of these is very rare and the second unstable and tends to decay into calcite), and it is even more common in non-crystalline form as limestone and chalk (although modern chalks are artificially prepared and purer than ancient chalk, often referred to as "whiting"). Pure forms of calcite are usually white or clear, though impurities can cause it to take on almost any colour. It often is found as part of other rocks (see the notes on lapis lazuli). The form found in pigments is typically chalk, used for white paint or to change the brightness of mixed pigments. This is the reason it was often known as "whiting" (Trojan whiting, Spanish whiting, etc.) It was not often used with oil pigments, except as a translucent effect, because it is almost transparent in oil (Rembrandt seems to have used it to be able to pad out his more expensive colors), but chalk was often used as a white in tempera. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Carmine | (See Kermes) | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Chalk | (See Calcite) | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Charcoal | (See Lampblack) | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Cinnabar | HgS Mercury Sulfate | Red or red/brown | Sometimes called vermillion. Ores usually found in Spain, Italy, the Balkans. A very
vivid red, but rather dangerous to deal with because it was relatively easy to liberate
the mercury -- and mercury is toxic, and some of its compounds even more so.
Another name occasionally used for it is minium,
although that name is more frequently and more properly used for red lead (Pliny
referred to cinnabar as the best form of minium and to
red lead as minium secondarium, second-rate minium,
or "false sandarach" presumably because it was cheaper
but not as bright as cinnabar, but Gerber, who eventually became a more
important authority, reserved the term minium for red lead). In early
times, cinnabar seems to have been mined (generally meaning that it was not
very pure, and indeed, artists were warned to buy it as stones rather than
already ground, as apothecaries might adulterate the ground form).
Later, purer forms were created from elemental
mercury (often derived from natural cinnabar!) and sulfur. Even artificial cinnabar
may not have been ideally pure; the recipe I've seen called for one parts mercury by
weight to two parts sulfur -- which means that there were twelve times as many sulfur atoms as mercury atoms! Given that pure mercury sulfate would have equal amounts of sulfur and mercury (by number of atoms, not weight), the excess of sulfur is astonishing.
Although known to the ancients, it has been claimed (I do not know how accurately) that cinnabar became popular only in the Middle Ages, under Moorish influence. Supposedly, in early times, it was as expensive to cover a page with cinnabar as gold -- but I have never heard of a cinnabar/vermillion codex. A sixteenth-century English document describing inks of various colors reports making red ink by beating egg whites and adding vermillion. Although it is a beautiful orange-red, cinnabar was not very suitable for use in mixed colors such as purples because of its orange tint, so other colors such as the so-called "red lakes" had to be used for mixing. And it doesn't look very good in oils, so it became much less popular as oil painting took over. And, finally, although it is stable in conditions of low light, if exposed to bright bluish light, the red cinnabar can convert to black "metacinnabar," so the color could darken and lose its vibrancy over time; it is likely to look brown rather than bright red. It was said to be particularly subject to degradation if used in fresco. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Celandine | complex organic | yellow | A mix of mercury and egg yolk produced a silvery sort of ink, which could look like gold if a yellow color was added. Apparently the juice of the celandine plant was often used to supply this yellow. However, the color did not last long and will usually be faded. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Chrysocalla | Copper Silicate, CuO3Si | green | One of several copper silicate pigments (see also Egyptian Blue), this one is greenish and is a common modern pigment but in the past was apparently used primarily as a binder for gold; it was sometimes called "gold glue." | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Cochineal | (See Kermes) | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Dragon's Blood | complex organic | reddish | A purple-red resin-based compound, difficult to identify because it looks much like other reds, but almost certain to be old (it is no longer sold). It reportedly came from the Arabian Peninsula and beyond, from a shrub called Pterocarpus draco, (others suggest that the source is the rattan palm Calamus draco; evidently the color name and the plant name are closely linked). In either case, it is an oriental plant, so it was probably more common in eastern manuscripts.
Its primary purpose is said to have been to add a bit of color to metals, e.g. to make gold look a little more reddish. It wasn't particularly useful in other contexts, since it could darken over time or react with other chemicals such as white lead. It appears a few alchemists referred to cinnabar by the name Dragon's Blood (and, to add to the confusion, to call Dragon's Blood "Indian cinnabar") which might explain how the name arose, but I know of no artists who call cinnabar by that name. In later years, Avicenna was reported as saying Dragon's Blood came into existence as the result of a battle between a dragon and an elephant, in which the elephant sat on the dragon's tail and made it bleed, whence the name. (Another version claimed that elephants had cool blood, and that hot dragons sought it to cool off, and so they fought, and the mixed blood was Dragon's Blood.) | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Dyewoods | complex organic | typically red | Dyewoods are a large group of colors derived from the ashes of burnt wood. The most familiar sort was brazil wood -- and, yes, the name for the wood came before the name of the country; Brazil, the story goes, was so named because it became a major source of dyewood. (Brazil-the-color's name is said to be from Spanish braza, glowing coal; compare English brazier.) The way the ashes were treated would affect the color and permanence of the pigment, and are probably too complicated to be worth discussing here. They became popular relatively late -- apparently Brazilian red did not become really widespread until the fifteenth century. Brazilian red is, however, very subject to fading, especially if exposed to light -- more so, it is said, than European dyewoods; this might perhaps be used as a hint about a manuscript's history. Some other dyewoods are logwood, quercitron, and sumac. In the eighteenth century, dyewoods were important in producing black dyes (a dark red dyewood plus indigo produced a pretty good black), but such a use would not have been needed in manuscripts, where lampblack produced a better black. A sixteenth-century English document describing inks of various colors reports making russet ink from brazilwood shavings mixed with egg white and tempered with alum or gum. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Egyptian Blue | Copper Calcium Silicate, CaCuSi4O10 | Blue | This has been called the first artificial pigment, although the name "Egyptian Blue" is modern. It is not known how it was prepared in ancient times, but it is used in many Egyptian monuments, and the color on them survives to the present day. I have found no reports of it being used in Greek or Latin illuminated manuscripts, but it might someday turn up in documents from Egypt. In modern times, sometimes called "Alexandrian Blue." The Romans cometimes called it cæruem Puteolanum."
| Folium | (See Turnsole)
| Gesso
| CaSO4-1/2H2O | and other materials (White)
| Not really a pigment; gesso is a substrate, used to attach pigments or (often) gold leaf; it is a combination glue, colorant, and surfacer. Later, when canvas replaced wood as the usual surface for paintings, it was often used to smooth the rough surface of the cloth. The basic ingredient is slaked Plaster of Paris -- hydrated calcium sulfate, usually purified. It was often prepared by heating gypsum to drive out the water, then rehydrating it to achievethe exact desired consistency. (This could be thick and stiff or thin and runny, depending on the particular purpose in mind. A thin gesso, for instance, shrank upon drying, meaning that it achieved a better "fit" to a particular surface.)
| There were other ingredients, however. Many mixes include significant amounts of white lead for color (up to 25%). Gesso that was to be used as a substrate for gold leaf often had Armenian bole or another reddish earth added (so it would be less noticeable if the gold rubbed off. The red was due to iron oxides). Sugar might be added as a dessicant, and gum to make it cohere better. Finally, water and egg glair (made from egg whites) would be added, the former to moisten the mix so it could be applied to the page, and the latter to make it stick. When applied to manuscripts (as opposed to walls or the like), it was applied with a pen, then allowed to harden. The overall effect seems to have been rather like water-based correcting fluid. After it had dried, a layer of gold leaf might be burnished on top of the gesso (usually after waiting at least a day). Sometimes gesso was placed behind other pigments as well. It is likely that this was done to brighten the pigment -- it would not change the color of the painting, but it would cause it to reflect any light which passed through. The effect was a bit like painting over a mirror. For more on gesso, see the discussion of binders above. Gold | Au | Golden
| Gold was used to represent, what else, gold; it was either applied as a thin
sheet (gold leaf) or ground up to use as an ink. Obviously this was done only
in the most expensive manuscripts. When the patron could afford it, however,
it was usually used both for golden shades and for yellows. Also, on very rare
occasions in the late Middle Ages, it was coated with a transparent layer of
another color to produce, say, a metallic red.
| Ground gold was rare for another reason besides expense: because gold is so soft, it was very hard to grind; the particles tended to stick back together. It helped to mix the gold with salt or honey, and grind the mixture, then wash away the intrusive material, but no technique known to the ancients could make the particles small enough to make a good suspension, so gold ink had to be applied in a thick layer, using a lot of gold. This made gold leaf a better economic proposition: you could cover a lot of page with leaf for the equivalent of the cost of a little gold ink. And the leaf looked better and shinier. Eventually another method was developed for writing in a golden color, known as mordant gilding: a sticky material was used to write on the parchment, then gold leaf pressed on it. The gold would stick to the glue and not to the parchment, so the writing would be gold and the rest of the leaf could be reused. But it was hard to produce attractive writing this way; the boundaries between parchment, glue, and gold were often not very sharp, and the adhesive might get smudged. Some glue mixes were colored red to try to make this less obvious, but the method was never really perfect. And the mordants were often water-sensitive and gradually affected the gilding; the response to this was oil mordants -- in effect, sticky varnishes -- but I believe this technique was not developed until quite late. Yet another trick for applying gold was to use a mordant and some sort of rough material such as ground glass, and then rubbing it with a lump of gold; the rough material would cause the gold to flake off and stick to the mordant. This was "attrition gilding," but it probably wasn't very common, because it was complicated and you got a rough page that wouldn't be good for the facing pages. Note also that gold ink was not very visible against ordinary parchment; it really only worked on parchment died purple or some other dark color. So gold ink, already expensive in itself, required unusually expensive parchment as well. All in all, very un-economic. There is an important bit of terminology about applied gold. Gold leaf isn't just a thin layer of gold -- a thin layer of metal is a foil (as in aluminum foil, tin foil). Foil is about as thick as a sheet of paper. If the layer of metal is even thinner than that, it is leaf. When gold was applied to parchment, it was leaf gold, not foil gold. Many other metals, however, might be applied as foils, because it was much easier to beat gold out to leaf thickness than to prepare tin or copper at such thickness. In general, gold leaf would have gotten thinner as time passed. This was not for economic reasons; it's that the techniques for making it improved. Very thin gold leaf easily sticks to things, so it had to be prepared on a special sort of parchment called "goldbeater's skin," which was not developed until the Middle Ages. When gold was used -- either leaf or ink -- standard practice was to burnish it after application; this assured its smoothness, and hence a golden reflection; if this was not done, the reflection would be yellowish but not metallic-looking. Unburnished powdered gold was sometimes used as a yellow pigment, but the wastefulness of this will surely be obvious. Burnishing in manuscripts at this time was usually done with a tooth, with the teeth of carnivores preferred because of their hardness, although in larger drawings, where the gilt area was large, a smoothed stone had to be used. Hematite was often used for this purpose. Occasionally gold was overlaid with paint, and the paint tooled or scraped off in elaborate patterns. This was known as "sgraffito" (the general technique of mixing patterns was "damask"). Gold as a pigment had the advantage that it did not tarnish -- but it also had the disadvantage that it scrateched easily. For this reason, it was sometimes the practice to put silk "curtains" over illustrations made with gold to prevent the gold from being damaged. Green earth | Ferric and ferrous oxides plus silicates | Green
| Often called terra verde or terre verte,
with the same meaning as "green earth"; also sometimes as "Verona green." This is said to have been the most common green pigment
in the middle ages; it was a by-product of iron mining, or was sometimes found on its own. Although chemically stable and widely available, and usable in almost any medium, artists seem to have felt some distaste for it -- probably because it wasn't very bright. Later it came into even poorer repute because it had poor hiding power in oils. As a pigment, it was a rather dull green, of varying hue, from olive-green to apple green. (Different localities were known for their different shades of green earth; Bohemian was known for being the truest green, Cyprian was more yellow, Verona's version more blue, and Tyrolean a dull blue). Sometimes it was used in layered paintings to give a more realistic tone to faces which were colored with white lead and a red shade -- but this, obviously, was a lot of work, so I suspect this is rarely encountered in manuscript illumination.
| Its chemical composition varies, being mostly a mix of minerals, glauconite and celadonite. Ferrous oxides (Fe2O3; see Hematite below) and silicates seem to be the other common components. Celadonite, which is a light green with perhaps a bluish tinge, was most strongly associated with Verona and northern Italy; glauconite, which was more yellow or olive, was brought from the Czech regions. Little research seems to have been done on distinguishing where and how the various green earths were used. Being dull colors, they were more likely to be used for backgrounds than for primary features of an illustration. Hematite | Fe2O3 | Red
| As a mineral, hematite (essentially, rust) is usually black, so it isn't often used as a paint, but it streaks a streak plate with red, and so is used to make red inks -- it was the usual red ink in Egyptian papyri. See also red ochre, which is essentially the same mineral. (The color of hematite is strongly dependent on particle size. Large particles are black or purple-black; particles about .1 micron in size are red; particles of .05 micron or smaller are orange. So the appearance of the ink depends strongly on how the hematite is ground.)
| Honeysuckle Green | (complex organic) | Green
| One of many greens made from plant juices, this recipe probably
originated in an Arabic-speaking country, for many of its early names
seem to be debasements of the Arabic word. The green probably derived
from the chlorophyll in the plant's leaves. It was not very common.
| Indigo | (complex)
| Blue | Greek Ινδικος (although this is a tertiary meaning; the primary meaning is "India.") One of the earliest known permanent dyes, found in both indigo plants (from Asia; the name "indigo" evidently derives from "India") and woad plants (known, e.g., in Britain), although the concentration in woad is far less than in indigo plants (which apparently led to early protectionist measures as European dyers who used woad tried to block importation of indigo). The blue color itself, technically known as "indigotin," is the color of "blue jeans," which are colored with indigo. It was also used as a medicine, being a powerful astringent. The chemical is complex (if I counted right, it has three sodium atoms, thirty hydrogens, 35 carbons, three sulfurs, two nitrogens, and nine oxygens; there are four benzene rings, one modified benzene ring, and three NaSO3 groups). Nonetheless it is produced by many plants, and has been synthesized by moderns -- there are even bacteria which have been modified to produce it. It is not as rich a blue as lapis lazuli or the copper compounds, and suffers from the fact that it is not very opaque (it is a far better dye than pigment. This was especially true before around the year 1100; better purifying and dyeing methods were developed at that time) but was used because it was more available than the truer blues. Although the supply even of woad was rather limited -- it was a plant, but one that tended to use up the soil if cultivated. (Indigo, by contrast, fixed nitrogen, so it was less damaging to the soil. Indian indigo as a result was very much in demand in Rome and the west.) In an era before fertilizers were widely known, a few years of cultivating woad would leave a field no longer capable of sustaining a crop.
| Interestingly, although indigo is a better dye than pigment, it is easier to prepare as a pigment (dying with indigo involves a complex chemical stew, and the indigo for a time is transparent; it is not obvious how dyers learned how to do it); Roman shields are said to have been colored with a paint based on powdered indigo. And dying with indigo could be done with a cooler dye solution than madder, the other major dye of the late Middle Ages, which had to be heated. Indigo could not, however, be used in frescoes. For another indigo-based color, see Mixed Green. Indian Yellow | magnesium euxanthate | Yellow or yellow-orange
| Apparently known from ancient
times in India and surrounding regions. It is usually stated that it was made
from the urine of cows fed on mango leaves -- a practice outlawed in 1908 as it is
hard on the cows. It should be noted, however, that Victoria Finlay tried to
investigate this process in the part of India where the product was made, and
couldn't find anyone who knew anything about it. (And certainly there were a lot of fake Indian Yellows not made by this method.) Indian Yellow did, however, smell pretty
bad, so there is probably some truth to the story. The name in the Middle East
seems to have been purree or something similar (puri, peori).
Whatever the original source,
the pigment can now be made with magnesium and euxanthic acid
(C19H16O10). It reportedly did not make
its way to the west until the nineteenth
century. Thus its presence in a manuscript illumination of a Latin manuscript would
indicate a very late date, although a Greek or Syriac manuscript might have contained
it earlier.
| Iris Green | (complex organic) | Green
| A rare but very attractive green, made from the juice of iris flowers plus
alum. It was commonly used for manuscript illumination in the fourteenth and
fifteenth centuries, but rarely if ever before that.
| Ivory Black | (See Bone Black)
| Iron pigments | (see red ochre, yellow ochre,
green ochre under Ochre; also Hematite)
| Jade | usually jadeite, sodium aluminum silicate,
NaAl(SiO3)2; sometimes nephrite,
Ca2Mg5Si8O22(OH)2
| (many colors, but often green)
| The informal name "jade" is used for two different minerals, both found
in large enough blocks to be suitable for sculpting, but attractive enough to be considered
a semi-precious stone. Jades range in color from white to green to black; green jade is
probably the most desirable, and was used in eastern countries to produce the pigment
known as "spinach green." I gather that this form was occasionally ground up
to produce a green pigment, although this was more common in the east; I do not know of
instances of green jade in western illuminated manuscripts. But my knowledge is far from complete!
| Kermes
| (complex) | red
| This pigment is believed to be the one referred to in Genesis 38:28; indeed,
the word "crimson" is said to derive from kermes. The word
"kermes" itself reportedly comes from from Sanskrit "kermidja"
"(made) from a worm" -- a fitting name, because
kermes was not prepared from a mineral but from the bodies of small red insects
which inhabited evergreens along the Mediterranean. This or something similar
can also be found under the name "cochineal," although this color (which
can sometimes be more purple than red) is not very stable under light -- especially
if it is not treated with alum to fix it. (Complex organics such as kermes are rarely
as stable as simply mineral dyes, and the most common uses for kermes and cochineal
and other insect-based red colors in painting was in "lake" pigments where the kermes supplied the color and the lake made it opaque; such pigments were almost an
invitation to fading. There was a complex process that made it quite color-fast, but one suspects it got messed up frequently.)
| Despite its name giving rise to an English word, Kermes can't have been common outside the Mediterranean (although it is said to have been used in the Lindisfarne Gospels), because it took a tremendous number of bugs to produce a relatively small amount of pigment. (This is also true of cochineal, which came from bugs on the knawel plant. Cultivation was complex -- you had to pull up the plant, which was a perennial, during a window of about two weeks, pull off the insects, replant the plant, and then process the bugs.) Supposedly the kermes was extracted from the insects by drowning them in vinegar or killing them with vinegar fumes. (Modern kermes insects, it is reported, are not easily killed this way; perhaps they have evolved an immunity to acetic acid.) Interestingly, the Americas also boast a pigment, carmine, derived from the bodies of insects (both insects reportedly being of the cochineal family). In recent years it has become a major commercial product in Latin America, where there are farms of prickly pear cactus set up to support the insect. (This is a much more successful industry than the old kermes trade, because the carmine insect produces more of the chemical than the kermes bug; the kermes trade all but collapsed in 1884 after a dye called Congo Red was synthesized that could color cotton red.) The name carmine is also derived from kermes. ("Cochineal," on the other hand, comes from Spanish "cochinilla," itself perhaps from Aztec "nochezli." The Spanish for long actually transferred cochineal with their treasure fleets, as they did with precious metals, and kept the source secret; they shipped the dead bugs to Spain for processing) Carmine and kermes are not the same chemical, but they are closely related. The proper name of carmine is 7-D-glucopyranosyl-3,5,6,8-tetrahydroxy-1-methyl-9,10-dioxoanthracene-2-carboxylic acid. Not too surprisingly, this is sometimes called by the shorthand "Carminic acid." Kermes has as its active ingredient "Kermesic acid," which is chemically similar but not as complex (both have the same structure of benzene-like rings at one end, but there is a chain of carbons and hydroxyls at one end, and the chain on carminic acid is four links longer). Around 1610, Cornelius Drebbel found a way to make carmine into a kermes-like color, but this probably doesn't affect manuscripts much. It will perhaps make some readers less than happy to realize that cochineal is an approved red food coloring, used e.g. in certain candies. Also, the robes of Roman Catholic cardinals came to be colored with kermes after the Tyrian purple that had formerly been used became too hard to obtain (a change reportedly made by Pope Paul II in 1467). Other names for insect-based reds are the Latin vermiculum and English grain/greyn, which although it sounds like it refers to a cereal is in fact a name for crimson. There is at least one Middle English reference to "crimson in grain" as a dyed cloth. There is also "Polish cochineal." All these names probably go back, in some form, to kermes, which seems to have had many names in antiquity. Because the bugs involved resembled berries, Theophrastus called it "κοκκος," which became Latin "coccus" -- a term used by Pliny -- who however also called it "granum," "grain" -- indeed, he called the insects a "berry which becomes a worm." "Grain" also went into English as another name for scarlet (the word "scarlet" itself was once a term for a cloth type that came to be applied to a color instead). In Christian usage, Jerome called kermes insects "baca," "berry," but knowing it came from an insect, also used "vermiculum," "little worm," whence "vermilion." Some have said that the Hebrews used Kermes to dye the curtains in the Temple. This obviously is beyond proof, but it is not unreasonable that Solomon would spring for such an expensive but excellent color. (And expensive it certainly was, since it supposedly took about 150,000 insects to produce one kilgram of the color!) There are some amazing stories about kermes being used for tribute in Roman times, and about wild escapades by nations and individuals trying to gain a part in the kermes or cochineal trade. Those interested may refer to Victoria Finlay, Color: A Natural History of the Palette. This book has information on some of the other colors listed here as well, but the kermes story is perhaps the most adventurous.... Those who study alchemy may find references to a kermes mineral, but this is certainly not the same substance, although it is far from clear what inorganic compound is being referred to. Kohl | Lead (II) Sulfide, PbS
| Black
| Used primarily as a cosmetic but perhaps sometimes found as a pigment. It isn't really a pure compound; the main ingredient, galena, is mostly lead sulfide but is often contaminated with other minerals, and often there were other lead compounds, such as white lead, mixed with it. So it could be black (if the proportion of lead sulfide, which is black, was large) to dark grey (if there were more contaminants).
| Note that lead sulfide was the result of white lead being exposed to sulfur. Thus kohl was what you got when white lead turned black. Lampblack | Carbon, C
| Black
| Pure carbon is one of the purest blacks known, and as such was used both in ink and
in paint to supply blacks and mixed tones. Its use reportedly goes back to ancient
Egypt, at least 1500 years B.C.E. It has always surprised me that so many inks
did not use lampblack -- but poor monasteries which used mostly natural lighting might have
a limited supply, and lampblack -- being a non-acidic suspension -- would not cling to the
parchment as well as more acidic inks. The problem of limited supply could sometimes be
solved by creating carbon by other means, e.g. bone black. Also, gum might be added to
bind it to the parchment, or a gall ink might be included to burn it in to the surface
of the material.
Because it was thin and did not mix very well, lampblack was rarely used in mixed
pigments, and only occasionally in pure blacks. It was primarily an ink, not a
pigment.
| Today, carbon black ink is often known as "India ink." Lampblack was not the only ancient form of carbon. Charcoal is also basically carbon. Many sorts of charcoal were made, from vine branches to ivory chips. (Charcoal was sometimes known as "vine black." Since it had more impurities than lampblack, it was poorer pigment.) Some were nearly pure carbon, others had substantial impurities. These might affect both the color (or, at least, how black the black was -- willow charcoal, for instance, was notably gray rather than black) and the graininess. Thus lampblack was clearly the best ink, but a charcoal might be the best pigment for a particular purpose. If you see Carbon Black today, it nominally the same product as lampblack -- pure carbon. But modern carbon blacks are made from natural gas and are chemically more pure; it is possible for chemists to tell them apart based on the impurities in lampblack. Lapis Lazuli
| [lazurite: (Mg,Fe)Al2(PO4)(OH2)] and others
| Blue | Unlike most common pigments, lapis lazuli is not a simple compound.
Rather, it is composed of lazurite mixed with calcite and often small amounts of other compounds such
as pyroxenes (including iron pyrite, or "Fool's Gold").
Lazurite, the key component, is a deep blue compound, sometimes called
ultramarine, although the name ultramarine originally applied to lapis lazuli
itself. The name "ultramarine" was given because the material had to
be imported from far away, often over the sea.
(It should be noted that lazurite does not refer to a specific mineral but to
several closely related minerals with different amounts of sodium, sulfur, and
calcium. It was not until it was artificially reproduced that lapis lazuli
became a truly standardized color.)
In natural lapis lazuli, the calcite generally serves to lighten the color of the rock;
lapis lazuli is always blue, but how dark a blue depends on the exact nature of
the mix. Sometimes an artist would go so far as to use chemical processes to
purify it, although this was much more common in later eras than early; it
wasn't until the late middle ages that dark blues from lapis lazuli became
(relatively) common. It was not until the late 1820s that chemists found ways
to create artificial lazurite.
| The stone is considered a semiprecious gem, and the best source for lapis lazuli is said to be Afghanistan. In the past, it was brought west along the Silk Road from the Sar-e-Sang, so there is some geographic variation in its frequency of use -- it is said that it is more commonly used in Italian manuscripts, much less so in books from northwestern Europe. A manuscript which uses it extensively is most unlikely to be from Germany or Scandinavia, e.g. It was rare enough that there are reports of it being scraped off manuscripts for reuse. Indeed, it is said to have been the most expensive pigment known to the ancients other than gold; a writer complained in 1508 that it cost 100 florins per pound. (For this reason, there was a significant tendency to use it in conjunction with gold, to make a really expensive manuscript.) It has been hypothesized that Michelangelo's unfinished painting "The Entombement" was left incomplete because no one could find or afford the required ultramarine paint. In Europe, the earliest firmly dated use is said to be in Rome's San Saba church, from the early eighth century. In addition to its rarity, lapis lazuli required very complex handling in order to extract the desired color. Modern methods involve materials such as linseed oil that the ancients probably would not have used, but they likely had some sort of grinding-and-kneading procedure to extract the color; the impurities needed to be controlled and it couldn't be ground too small or it wouldn't be as deep a blue. This was work enough that it might have added still more to the price. Byzantine illuminations using lapis lazuli have been dated as early as the seventh century. In the late middle ages, it was largely displaced by smalt, which is a less attractive blue but was cheaper and had better hiding power. More recent preparations from lapis lazuli would try to separate the blue crystals from the calcite and others to produce a more intense blue. This is not a good indication of date, however, because the effects will depend on just how pure the original stone was. Modern ultramarine blue pigment, which different sources date to 1814 or 1829, is chemically identical to lapis lazuli, and will look much the same at a casual glance -- but because the lazurite is prepared artificially, the particles are much smaller than in lapis lazuli paint; microscopic examination can often distinguish them. In addition, early ultramarine often contained some sulfur which made it look somewhat more purple. Ultramarine was considered a blue for (dark) skies, as opposed to azurite (occasionally referred to as aquamarine), which was for sea blues. Because it was so rare and expensive, ultramarine would become the standard color in medieval illuminations for the clothing of the Virgin Mary; almost all illustrations show her gowned in blue, and it was considered somewhat scandalous when a later artist showed her wearing red. It is said that lapis lazuli would sometimes degrade to a gray and develop splotches, but no chemical mechanism has been discovered for this and it happens only rarely; I suspect some sort of impurity. Red Lead
| Lead tetroxide, or Lead (II, III, IV) oxide, Pb3O4
| Red | There are actually two red oxides of lead, lead oxide (also called lead monoxide), PbO, or litharge, and lead tetroxide, Pb3O4 (also called lead peroxide), sometimes known as minium -- although that name is sometimes, confusingly, used for cinnabar; see the note there. Vitruvius and Pliny called lead tetroxide sandaraca or sandarach, a name also used for realgar. The name "stupium" was also used, and "miltos," plus "sinopus" by confusion with red ochre. The consensus among those who described all the colors is that "minium" should be used as the name for red lead. The name "minium" also gave rise to the verb "miniare" meaning "to work with minium" and even, less directly, to our word "miniature." One who applied red lead was a "miniator".
| If we cut through all those other names, lead tetroxide is what is usually known as red lead, and was prepared by heating white lead. Lead oxide was made by simply heating lead metal and allowing it to oxidize. I suspect, since ancient red lead is sometimes referred to as orange, that it was sometimes a mixture of oxides, since another crystaline form of PbO formed yellow crystals (see yellow lead). Red lead was used notably in the Lindisfarne Gospels to produce a sort of red shadow for the outlines of letters. It is said that over 10,000 dots of red lead were used on one of the pages of that gospel (beginning of Luke, where every letter is outlined in two or more rows of dots). It was known as a poison at least from the time of Nicander of Colophon (second century B.C.E.). For some reason -- perhaps because of its dangers -- use of red lead tended to decline over time, with vermillion becoming a more popular replacement. If you ignore its poisonous aspects, it is an excellent pigment, with a clear red color, good hiding power, and small particle sizes that make it easy to mix and apply. As a result, in addition to its use as a pigment, it has sometimes been used as a primer, binding to the page (or other materials such as metal), with a second, harder-to-appy, pigment being laid over it. The Romans seem to have used it extensively as a wall paint, which can't have helped their health. (In medieval times, litharge was actually used as a medicine, applied to England's King Henry IV. He was already sick, which is why they applied it, but perhaps it's not surprising that he ended up dying young!) Red lead, like white lead, could turn brown or black when exposed to air; this was particularly a problem in frescoes, but it happened in books, too, unless the lead was varnished or otherwise protected. White Lead
| Lead acetate: lead (II) ethanoate, Pb(CH3COO)2 (sometimes called lead carbonate)
| White | Greek ψιμυθιον; later sometimes called Flake White. The basic white color of ancient times. The standard ancient method for making white lead was to take sheets of lead and place them in a pot (which had never been used for anything else) and cover it with vinegar, then let it sit for a month. Once it had finished reacting, the result was heated until it turned white. White lead was used both
as a white paint and as a whitener (that is, it would lighten the shade of other
paints). A sixteenth-century English document describing inks of various colors reports making a white ink from white lead. Unfortunately, it decays over time to toward dark shades (the result of
exposure to hydrogen sulfide), producing artwork
which often looks very strange (since, the lighter the original color, the
darker the final shade). Also, it could not be used in frescoes. It was sometimes referred as ceruse. It was known as a
poison at least from the time of Nicander of Colophon (second century B.C.E.).
Modern paints based on white lead often contained mixtures of compounds, perhaps
70% white lead and 30% lead hydrate.
White lead has another interesting use: It can sometimes by employed to reveal when
a painting has been corrected. It was the original "white-out," used to paint over
a mistake. And, because lead is very heavy and stops x-rays, these corrections will
show up as a blank area if a painting is x-rayed. Titian's "The Death of
Actaeon," for instance, shows that the artist re-did the image of Actaeon
himself. Whether there are manuscripts which have been re-painted enough for this
to matter I do not know.
| White lead's opacity -- which made it a good correcting medium -- was another reason it was so widely used; the other whites (bone white and chalk) were translucent. It was not until lake pigments came along that there was a good alternative to white lead for opaque whites. White lead also had the advantage of being cheap -- one of the cheapest pigments available; there is a price list showing it costing only one-one hundredth as much as azurite. See also kohl, which often contained some white lead, and which was largely lead sulfide -- the black that white lead decayed into. Yellow Lead
| Lead chromate: PbCrO4
| Yellow | As with red lead, there are two compounds which might be known as yellow
lead. Today the term seems to be used primarily for lead chromate, or chrome
yellow. I suspect, however, that the usual form known to the ancients was lead
oxide, PbO. (Supposedly chrome yellow and the related chrome orange
were not manufactured until the early
nineteenth century. Chrome yellow was actually a mix of lead chromate and
lead sulfate, with the shade of yellow determined by the mix.)
Note that this lead oxide is chemically identical to the
lead oxide form of
red lead. The difference is in the structure of the crystals, with one form
being converted to the other by heat. This would theoretically allow the
possibility that red pigments would turn yellow over time, but since the
heat of conversion is in excess of 400° C, this would not have happened
extensively. Yellow lead oxide was apparently known as massicot (although pigments called "massicot" sometimes had a bit of a reddish tinge), and perhaps
as giallulinum. A sixteenth-century English document describing inks of various colors reports making yellow ink from yellow lead ground up with the fingers.
| The yellow lead industry was large enough that there was actually a standard way to distribute it: it was shipped in the form of tubuli, or tubes of yellow lead wrapped around an iron rod used as a core. There were also yellows which were mixes of yellow lead with tin compounds, and, most confusingly, these too were known as massicot, giallulinum/giallorino/giallolino, genuli, and plygal. A "lead-tin yellow" began to be used around 1300, also known as masticote, and became quite popular -- only to die out, with no known explanation, around 1750. It was not rediscovered until 1941. It is a little more orange-gold than pure yellow lead. The presence of this lead (as marked by tin signals in the spectrum, e.g.) does not prove that an illuminated manuscript is forged, but it hints at a late date. Madder/ | Red Madder complex organic | red
| Derived from the root of the madder plant, Rubea tinctorum (and, probably later, some relatives). It was used primarily as a dye (first used in Egypt around 1500 B.C.E.), not a pigment, but sometimes could be mixed with other colors. One of the chief difficulties with madder was that it took a lot of processing to convert the basic plant matter into a useful colorant -- although it was worth doing with the dye, since it was one of the few red dyes that was relatively light-fast (raw madder faded rather quickly, but if fixed with alum, it was more stable). The active chemical was alizarene (called "alazarin" when produced by industrial rather than natural means, as is usual today), C14H8O4, an orange-red. Alizaren was the first natural pigment to be artificially replicated (and it swept away alizaren from natural madder in less than fifteen years, causing significant economic distress) so its use in a drawing, while not proof of a forgery, is indicative. The color is not likely to be found in an early Western manuscript since it was not widely used until the late Middle Ages (Europeans were said to have learned of it after the Crusades, although I've read that it was used in a mural at Pompeii); its heyday was the seventeenth to nineteenth centuries. It was used far earlier in the east.
| Malachite
| Cu2CO3(OH)2 | copper carbonate hydroxide green | Frequently found in the same deposits as azurite, but more common. The properties are similar -- e.g. it is hard and requires much grinding to use. It is, however, more chemically stable -- azurite sometimes turns to malachite, causing blue pigments to turn green, but the reverse does not happen. A more modern formulation has been sold under the name "mountain green," but it is no longer used as a pigment in the west because it does not work well with oil. As a pigment, it had the difficult characteristic that it could not be ground too finely, because it lost its color. But it was so common that it appears the Egyptian word for green, vatch, is the same as the word for malachite. Like other copper greens, it was sometimes mixed with pine resin or bitumen to increase its chemical stability. See also verdigris.
| Massicot | (See yellow lead)
| Minium | (See red lead; also cinnabar)
| Mountain Green | (See malachite)
| Mulberry juice | (complex organic) | red or purple
| According to Pliny, the Egyptians used mulberry juice as a dye. In the Middle Ages, it was sometimes used as a blue dye, but was not color-fast. I have not heard of it being used in a manuscript, either as a dye or a pigment. The color perhaps was also known as murrey or morre; also Latin morum.
| Naples Yellow
| Lead antimoniate: | Pb3(SbO4)2 Orange-Yellow
| A synthetic yellow first found in the late middle ages, and used primarily in pottery glazes rather than paint (it isn't entirely stable unless it's covered with some sort of glaze or varnish, and like white lead, it turns black if it isn't protected). But it was known early enough that it is possible it could have been found in some late manuscript illuminations -- the Chaldeans used it as a pottery glaze during the time of the Babylonian Empire, and the Egyptians also knew how to create it, but it does not seem to have been common as a pigment until much later. (The way the Babylonians made it is unknown; no other ancient people seems to have adopted the method.) It may be the pigment Italians called "Giallorino." The eye pigment known as khol is also antimony-based, but does not seem to have been used in manuscript illustrations.
| A number of other antimony compounds were eventually used as colors, and since the element was known, it is possible (although not likely) that these might show up in a manuscript somewhere, especially in late medieval times. There is a pretty high likelihood that it will have degraded, however; most antimony compounds seem to have gone bad if exposed to sulfur, and they weren't very good with white lead. On the other hand, they aren't likely to be used in modern forgeries, having been replaced by cadmium compounds and others. Mixed Green | (complex) | Green
| There were many combination greens used by medieval artists. But, for some
reason, the combination of orpiment (yellow) and indigo/woad (dark blue) was so
popular that it was often prepared as a distinct color rather than being mixed on
the spot. So it perhaps should be considered its own pigment.
| Mosaic Gold | (tin sulfide) | Yellow
| The name is a rendering of Latin "aurum musicum." It may also have been called "mussif" or "purpurin." It is yellow but does not really resemble gold; some versions look more like bronze. It is apparently not entirely clear how it was first synthesized (the preparation is complex, requiring tin and sulphur plus catalysts and heat and pressure; one version also seems to call for mercury -- perhaps it included mercury sulfate, which is yellow); it seems to have come into use in the thirteen century. It does not seem to have been widely used in practice although there are several manuscript descriptions of it.
| Mummy | (complex organic) | Brown
| Yes, this is what it sounds like: a pigment made from ground-up Egyptian mummies! (One hates to think how much valuable archaeological evidence ended up being ground up just to get a slightly different hue of paint.) It is believed that what most chemists wanted from mummies was bitumen (Persian mumiya) -- but not all mummies contained bitumen, and if the chemists picked up a little of something else, so what? Mummy (sometimes called "Egyptian Brown" to hide what it was made from, or caput mortem, which doesn't seem like it would fool anyone) apparently began to be used in the twelfth century. There was supposedly an extremely high demand for mummy-the-color, and hence mummy-the-source-material, in the sixteenth century, and it didn't entirely cease to be used until the twentieth. I've never heard of it being used in a manuscript illustration -- though I'm not sure anyone would dare to test for it.
| Nightshade Green | (complex organic) | Green
| One of many greens made from plant juices. It was not very common, and
seems to have originated in the thirteenth century. The green was probably
from the chlorophyll in the plant.
| Ochres | Iron compounds | Various | Most natural ochres are a mixture of some amount of clay, quartz sand, iron oxides (hematite and limonite or geothite, or red and yellow ochre), and impurities; an important part of pigment-making is to get the quartz out of the natural ochre while leaving the rest. Often this was done by dissolving the soil containing the ochre in water; the sand sinks out, and the pigment materials stay in solution and can be recovered by evaporating the water.
| The ochres are among the oldest pigments known to humanity; there are neandertal grave sites with sprinklings of red ochre, and others with red ochre stones -- it is widely suggested that the bodies of the dead were coated with ochre, and the stones used as grave goods, although this is controversial. It is certain that red ochre is still used as a body pigment today by some peoples, and was valued by some tribes of Australian aborigines because of its use in drawing. Both red and yellow ochres were used for the Lascaux cave drawings. For the particular ochres, see below. Green Ochre | impure Iron (III) oxide hydrate | (green) |
Although one sometimes finds references to green ochre, this is not a pure substance;
it is yellow ochre with impurities, typically magnesium or aluminum silicates. See
also "Green Earth."
| Red Ochre | anhydrous iron (III) oxide: Fe2O3
| red/brown | See also yellow ochre below; also Hematite, which is the correct name for the mineral involved. It is also sold as red chalk. Red ochre, and other red iron oxides, have long been used as pigments, e.g. "Venetian red," as initially sold, was an iron oxide pigment. The color depends very much on the particle size; a lump of hematite will look purple-black, and coarsely ground hematite serves as a black color, but if ground down to a particle size of .1 micron or so, it will look rusty red -- tending toward orange if the particle is even smaller. For brighter reds, however, something such as cinnabar must be used.
| Red ochre, which is pure iron (III) oxide (Fe2O3) can be prepared from yellow ochre by baking the water out of it. Yellow Ochre
| Iron (III) oxide hydrate:
Fe2O3 • H2O
| Yellow
| Red ochre (the anhydrous form of hematite) seems to be the longest-known of the ochres, but for our purposes, the more common form of ochre is yellow ochre, which is the hydrate, sometimes known as limonite or geothite; red ochre will in time turn to yellow in the presence of water, so red ochre is found mostly in dry environments.
| Both forms of ochre are used as pigments; yellow ochre has the advantage over orpiment (another common yellow pigment) of being much safer to handle. But the color is not as brilliant, which is why orpiment is also used; for small areas of a drawing, yellow ochre just wasn't yellow enough to give a clear color. The modern colors raw sienna, burnt sienna (both named after the Italian town of Sienna where they came into widespread use), raw umber, and burnt umber are also based on iron compounds and are related to the ochres -- but they were not used in early paintings, which tended to avoid relatively dull colors such as browns; their use would be a likely indication of forgery. (And if you're wondering, yes, burnt sienna and burnt umbar were made by roasting, or "calcinating," the raw pigments.) A sixteenth-century English document describing inks of various colors reports making a "tawny" ink from "senna" and gum water; I would assume this is some sort of Sienna/ochre formulation. Modern, synthetic ochres are apparently sold as "Mars pigments." Although ochres are common, the impurities found in many of them made them rather poor pigments, because they lost much of their color when ground. So high-quality ochre was a special commodity. The best came from Sinope in Pontus, and so ochres were sometimes called "Sinopia." Ochre has another significance to manuscript historians, in that (under extremely limited circumstances) it can be used as a dating method. (This works better for murals and other artwork with a permanent orientation.) As an iron compound, ochre responds to magnetism, and when freshly applied, the ochre will align itself with the north and south magnetic poles -- then will freeze in place as the substrate hardens. Since the magnetic poles wander about, the way the ochre points can sometimes be used as a dating method. Orpiment
| Arsenic (III) sulfide: As2S3
| yellow
| Known in Greek as αρσενικον, whence the modern chemical name "arsenic" --
a name thought to be derived ultimately from Old Persian zarnikh, related to the word for "gold" -- although the form of the name caused it to be connected with male traits.
Probably the brightest and clearest yellow pigment known to the ancients --
so much so that the Roman Emperor Caligula allegedly tried to organize a project
to turn it into gold; in later times it was called King's Yellow. There was also a small bag of orpiment in the tomb of Pharaoh Tutankhamen. The English name "orpiment"
is said to be a distortion of Latin auri pigmentum, i.e. gold paint. Early orpiments
were natural, but alchemists eventually synthesized it. We find
early mentions of it in Egypt (Leiden Papyrus, third century C.E.)
and Greece (Democritus, second century B.C.E.). It is frequently
found with realgar, another arsenic compound, with a reddish tinge; mixtures might
appear orange. Despite orpiment's brilliant color, it was somewhat hard to work
with; it did not mix well with other colors (e.g. it hastened the process by which
white lead turned dark, and could also cause other pigments such as folium and
red lead to turn), it didn't work well with oils or in frescoes,
and of course as an arsenic compound, it was fairly poisonous. (And, yes, the ancients were aware of it and warned that it should be treated with care. Mines for sandarach, which referred to several compounds but in this case probably means an arsenic compound, were so dangerous that Strabo said only criminals were made to work there.)
The compound was found in Macedonia, Asia Minor, and Hungary, so it perhaps would be
more common in eastern than western manuscripts -- although it is found in the Book of Kells, which is about as western as a manuscript can get.
| Orpiment is not entirely stable if exposed to oxygen (the arsenic sulfide slowly turns to arsenic oxide), and if so exposed, it not only loses its color but ceases to attach to the page, so it is another pigment that might vanish in the course of time; some say it could also damage the parchment as this happened. Nor could it be used in frescoes. Interestingly, the first artificial orpiments were more dangerous than natural orpiment; they were made from, and therefore tended to contain, arsenic trioxide, which is even more toxic than true orpiment. Alchemists sometimes referred to the arsenic compounds orpiment and realgar as the "two brothers," "two kings," or "two friends." For another orpiment-based color, see Mixed Green. Realgar
| Arsenic sulfide: | As4S4 (or As2S2 or As3S3) orange-red
| Chemically similar to, and often found with, orpiment, another arsenic sulfide.
The name is said to be from Arabic Rahj al ghar. It seems to have been used
primarily if not exclusively in the eastern Mediterranean and points east of there.
It is very rare in manuscript paintings, although it was sometimes used to preserve
glair.
In the east, it is used in wall paintings as well as illustrations, although it could not be used in frescoes.
Like orpiment, it is poisonous --
if anything, even more so; it has been called the most poisonous of all ancient
pigments. It is sometimes known as ruby sulfur, and was called sandaraca by Pliny,
although this name is more typically used for red lead.
Realgar is not very stable, especially under
bright light; it will decay into yellow orpiment, which is why most instances of realgar
paint look orange rather than bright red.
| Alchemists sometimes referred to the arsenic compounds orpiment and realgar as the "two brothers," "two kings," or "two friends." Pliny called realgar by the name "sandarach," which gave rise to Agrippa's name "sadaraca," although he also called it "rosgeel," which I imagine is a badly distorted version of "realgar" (or perhaps of another name, risagallo). Rouen Green | (See verdigris)
| Safflower
| complex organic
| red or pink
| Safflower can be used to produce red and pink dyes. Safflower seeds have been found in Egyptian tombs (and probably not as a food; Safflower is not pleasant to eat). But I have never heard of it being used in New Testament manuscripts. The pigment made from safflower is sometimes called "carthame."
| Saffron
| complex organic (C44H64O24)
| yellow
| A very delicate yellow, but chemically complex (the chemical diagram of
the molecule takes up a whole page, and I won't swear I counted its components
correctly); the ancients could not synthesize it, and had to rely on saffron
plants. (The pigment, which is
also a spice, comes from a very small part of the flower; it takes great numbers
to make a usable quantity of saffron -- supposedly 170,000 flowers to yield one
kilogram. And, even in modern times, the stigma have to be separated out by hand,
and even champions can only pick about one every two seconds. Plus
the flower blooms only briefly, and withers if not processed quickly, making it almost
impossible to mass-harvest it). So it wasn't often used due to the high expense, except in special circumstances (e.g. Alexander the Great supposedly used it as a hair dye).
But the fact that it was so expensive means that it is more common in manuscript illuminations (which were small, and given to rich patrons) than in paintings. A typical means of preparation was to mix it with glair (egg whites) and let it set for a day and a half before applying.
| Saffron eventually came to be farmed in large areas of Europe, leading at times to collapses in the market. I suspect that it would be possible, if a sufficiently detailed chemical analysis were done, to tell classic oriental saffron from more recent European saffron -- there were at least three species of plant called saffron, with the "oriental" saffron considered to be the best. But I know of no work being done on this subject. Salt Green | (See verdigris)
| Sap Green | complex organic | Green
| Just what it sounds like: A green made from plant juice -- although not
actually from sap; it was made from ripe berries of buckthorn plants. It was
made by taking the juice of the berries, mixing with alum, and allowing to
thicken. Since there were several species of buckthorn, the results varied
somewhat, but the color was generally an olive green. It might be mixed with
gum, but it was not rare for the dried juice -- which was thicker than most
plant juices -- to be used as a paint without
any binder. (Occasionally the juice was used without alum, but this color
faded very quickly. Even with alum, it was likely to fade over time.)
Today it is used mostly in watercolors.
| Sepia
| complex organic | brown/black
| This is, to moderns, a confusing name, because sepia has become a name for a color rather than a pigment (e.g. we see "sepiatone" photos). The original sepia was derived from the "ink" of the squid, which it uses as a smoke screen to escape danger. The ink was collected and made into -- ink. Although squid ink appears black in water, when used on paper it usually appears brown, and rather transparent (it's the same chemical as some forms of human melanin, the skin pigment). As a paint, it is nearly useless, because it is not opaque, but some manuscripts are written with it, and some drawings sketched with it. Preparation was relatively complex; the squid's ink sac was dried, powdered, and boiled in an alkali to extract the ink.
| Shell Whites | complex organic | White
| Made from ground-up egg shells (dried in a flame) or oyster shells. It appears these colors were not used as pure whites, but were used to lighten other colors such as verdigris or orpiment/blue mixes.
| Silver | Ag | Silvery
| Silver, like gold, was applied either as a thin sheet or ground up to use as an ink. The ink form was more common, since it did not tarnish quite as rapidly as silver leaf, but tarnish was a problem with all uses of silver in manuscripts. Sometimes silver leaf was lacquered with yellow to try to imitate the appearance of gold. The technique of applying silver as an ink, or as particles in suspension, was sometimes called "grisaille."
| Smalt | (see smalt in the section on
Chemicals Not Found in Ancient Manuscripts)
| Spinach Green | (See jade)
| terra verde | (See green earth)
| Tin | Sb | Metallic
| Occasionally used as a foil or a ground ink component, presumably because
it was cheaper than gold and did not tarnish as much as silver.
Sometimes tin leaf was lacquered
with yellow to try to imitate the appearance of gold, or a mix of powdered
tin and a yellow would make a yellow metallic ink. A metallic green
might be produced by covering tin with verdigris; a red glaze might also
be used.
| Turnsole
| complex organic | blue or purple
| Also called "tornsole." Made from seeds of plants in the Crozophora family, which had to be processed in complicated ways. Called "turnsole" because the plant turns toward the sun like a sunflower. It is a litmus-like chemical, blue, purple, or reddish depending on how much acid is mixed with it. (Litmus too is plant-based -- it comes from lichens related to those used to make archil.) The blue color of turnsole came out when mixed with alkali. It had some tendency to revert to purple over time, but rarely to go back to red; that required stronger acids than were common in ancient times. It was used primarily in manuscripts, particularly for a relatively light, transparent blue. The plant that gave rise to it was known by many names, such as "torna-ad-solum" or "morella;" also "folium" (although that was often the name for the dye rather than the plant itself). It became popular in the fourteenth century, and was used in part as a replacement for Tyrian purple. There is some dispute about which plants were used; I've seen it claimed that "true" turnsole is either extinct or forgotten.
| A sixteenth-century English document describing inks of various colors reports making a blue ink using turnsole plus ceruse (white lead), water, and gum. Tyrian Purple
| complex organic | purple
| This is a dye, not a pigment; it was derived from mollusks (although it required very complex processing after that; it required an ammonia fix, generally from stale urine), and was used te supply the purple color in the togas of Roman senators and emperors. It was very expensive, and the limited supply was largely reserved for clothing (for the logical reason that it was one of the few reasonably permanent dyes known to the ancients). Even had the supply been greater, it is unlikely that it would have been used in paintings, because (like most dyes) it had little hiding power. But it has importance for students of manuscripts anyway -- it was the dye that made purple manuscripts purple. See also Whelk Red, with which it was often mixed (and which was often called "purple" also; according to Ulpian, any red or reddish-blue dye other than coccus or carmine/kermes was "purple").
| Incidentally, purple and the other "murex dyes" such as whelk red were said by Pliny to smell pretty bad -- a mixture of rotten shellfish and garlic. Hardly surprising, given the source and preparation method! Interestingly, the use of Tyrian Purple can be used as a dating method for forgeries from the Renaissance and after, but not for modern forgeries. The recipe for the dye is said to have been lost when Constantinople fell in 1453, and was not rediscovered until an artificial version was made in the nineteenth century. Ultramarine | (see Lapis Lazuli)
| Verdigris
| (various)
| green
| Verdigris (vert de Grece)
is not the name of a particular chemical; it is what we call the green patina of reacted copper. There were at least three such compounds called verdigris. The most common was probably copper (II) carbonate, CuCO3. This is the patina that usually forms on copper; it might hydrate to form malachite. Near the seaside, however, or where there is a lot of chlorine, the patina might be primarily copper chloride, CuCl or CuCl2. These were not green, but the latter would hydrate to become copper (II) chloride dyhydrate (CuCl2•2H2O), which is blue-green. Finally, there is copper acetate, Cu(C2H3O2)2, which is the one of these which could be made artificially and quickly, by exposing metallic copper to vinegar fumes or hanging it over the lees of wine; Theophrastus and Pliny both describe how to make it, and Pliny called it "aerugo." Alchemists sometimes referred to it as "Spanish green" (a name that went into German as Grünspan, which is now the usual name for the compound in that language). It is possible that there were other verdigrises as well, copper tartrate or copper malate (the latter might form if apple vinegar was used to make the verdigris).
| All these forms of verdigris formed brilliant greens, but whether they were light-fast depended on the paint substrate. Da Vinci noted that it had to be varnished quickly if the color was to hold. It is said that no color, not even white lead, has deteriorated more in medieval paintings than verdigris. Verdigris is said to be stable in oil, but far less so in other media (so some sources; others think it was less stable in oil than in tempera, but the general sense is that it had to be guarded from air with varnish or something, meaning that it was not a good choice for manuscript illumination), although this would depend on the exact formulation used. Thus we sometimes find pigments which should have been green have turned to brown or near-black over time. (Ironically, in oil, verdigris was not very opaque and had to be mixed with other colors to improve its appearance -- or with turpentine, which made it even more likely to degrade other colors. That, combined with its color instability, seems to have led to a rapid decline in its use once oil painting came in.) A second difficulty is that it could not be used with white lead; the two reacted quickly to destroy the colors of each. (At least, that was what was said at the time, although modern chemists can't figure out why this would be so.) Orpiment didn't mix well with verdigris either. A third problem is that, over time, verdigris could damage the parchment below it, leaving paintings with holes where green pigment would be expected -- although a small amount of saffron in the green supposedly could stabilize this. It is said that verdigris in manuscripts has held up better than in paintings, perhaps because it hasn't been exposed as much. Verdigris was often used to make illuminated initials in manuscripts. A sixteenth-century English document describing inks of various colors reports making a green ink from verdigris. Alchemists seem to have referred to verdigris as "Seed of Venus." I know of no such references among artists. Sometimes a verdigris mix would be known under another name. "Rouen Green" was a name for verdigris made by coating the copper with soap (lye) before exposing it to vinegar (it was then supposed to sit in a sealed pot for two weeks to react); "Salt Green" was from copper coated with honey and salt before exposure. Like other copper greens, it was sometimes mixed with pine resin or bitumen to increase its chemical stability. Vermillion | (see cinnabar)
| Vine black | (see under lampblack)
| Weld | complex organic | Yellow
| The English name of the Reseda luteola, related to a garden plant called the mignonette. Mostly used as a yellow dye -- e.g. it was usually the color mixed with woad to produce the Lincoln Green you hear about in Robin Hood stories. Very occasionally used as a yellow ink, or mixed with a blue to produce a green color. However, the color was not stable in light, so it was rarely used in manuscripts and or paintings. It eventually came to be used in yellow "lake" paints, but this was mostly after the manuscript period; weld does not seem to have been commonly used until the fourteenth century, except as a dye (it was sometimes called the "dyer's herb" or "fuller's herb") -- although it was still used in that role until the twentieth century. It may be the oldest dye still in use; seeds of the weld plant have been found in neolithic burials, although no cloth survives from that period.
| Whelk Red
| complex organic | purplish red
| A close relative of Tyrian Purple, to which it is similar in both source and method of preparation. Indeed, because dark reds were called purple (πορφυρα, purpura) in ancient times, whelk red is a purple, it's just not the purple (although the best purple was made of a mixture of chemicals from two different mollusks, so one might say that Whelk Red is part of Tyrian Purple). Like purple, whelk red is a dye, not a pigment, made from mollusks (especially whelks, obviously). Its advantage over Tyrian Purple was that the shellfish involved were more common and widely distributed, making it somewhat cheaper than the true purple (although still very expensive). It was thus more likely to be used to dye manuscript pages. But it was also very variable (from a relatively pale magenta-like color to a darker purplish-red), presumably based on the exact source, so we often see (reddish)-purple manuscripts which show great variation in the color of the pages. See also Tyrian Purple.
| Whiting | (See Calcite)
| Wine black
| complex organic | blue-black
| Vitruvius reported making a black by burning dried dregs of win, and said that
the finer vintages could also give a color reminiscent of indigo. Presumably the black
is mostly from carbon, but I know of no details. If wine black was used for manuscript
illumination, I have not heard of it.
| | ||||||||||||||||||||||||||||||
Chemicals Not Found in Ancient Manuscripts
If the chemicals listed above can be shown to be ancient, certain pigments were not invented until after the manuscript era closed. If these colors turn up in a manuscript, the manuscript must be a recent forgery -- or, at minimum, it must have been repainted; there are some famous paintings that were restored using pigments (often yellows, since good yellows were so rare in medieval times) that weren't available when the originals were painted. Since paintings were more likely to be restored than manuscripts (a painting was necessarily exposed to air, whereas a drawing in a manuscript was usually covered, and a painting in any case was of no use if it faded, but a manuscript with faded illuminations would probably still have a readable text), it seems unlikely that many manuscripts would have had their artwork repainted.
As with the list of pigments above, this is not an attempt to list every color created since the manuscript era ended. Indeed, such an attempt would be misleading, because an individual artist might have created a new color, or extracted one somewhere. The pigments listed here are classes of pigments, identifiable by spectroscope, which are most unlikely to have been used in early centuries because they are difficult or dangerous to make and unlikely to be found in isolation.
- Aniline Dyes: There are very many of these, the first (mauve) having been created by Perkin in 1853. You aren't likely to see them used in painting, but they might be used in a color ink or to stain a parchment.
- Asphaltum: see Bitumen
- Barium Yellow: see Lemon Yellow.
- Bismuth colors, most notably bismuth white. Used mostly in the nineteenth century; it was not known to the ancients, and effectively went out of use when zinc white came in. Like white lead, being exposed to sulfur will turn it dark -- indeed, it is said to be more prone to discoloration than is white lead itself.
- Bitumen (also known as asphaltum): Yes, this is what it sounds like: the hydrocarbons left over after distilling petroleum. It was sticky, and it never dried, but it was considered a rich color. Rembrandt actually used it with success, but few others -- if more than a little was applied, it did much damage to the canvases on which it was used. In any case, it was not discovered until well after the manuscript era. (See, however, Mummy.) If you do encounter it in something that is claimed to be an early manuscript, the likely reason is that it is being used to make a new painting look older, so it is definitely a sign of a forgery.
- Cadmium pigments. Cadmium sulphides can range in color from yellow (the usual form of the pure material) to deep red (the reds usually contain selenium as well). They are made by working with cadmium metal, which was not isolated until after the manuscript period (in 1817, to be specific). Although the bright colors of cadmium compounds were quickly noticed, cadmium was extracted from zinc ores, and it was not until the 1840s that these were available in enough quantity to make cadmium a commercially usable element. The first cadmium pigments were put on the market around 1850. It is unlikely that they would have been used before that, partly because cadmium is rare and partly because it is highly toxic and difficult to work with. In appearance, cadmium red is quite similar to cinnabar, which it has largely replaced. Cadmium yellow also became quite popular, and there are mixes of the two to produce almost any desired shade of orange.
- Chromium pigments. Chromium is so called because its compounds come in so many colors; Chrome Yellow, Chrome Orange, Chrome Red, and Chrome Green are all commonly-used pigments (the former three being lead chromates; Chrome Green is Chrome Yellow plus Prussian Blue). The color know as viridian (Guignet's green, or verte émeraude, a bluish-green much used by Cézanne) also came to be a very popular pigment; it is a chromium oxide. It is just possible that some ancient might have found one of these pigments -- probably chrome yellow, which sometimes shows up with yellow lead -- and used it in a painting, but chromium metal was not discovered until well after ancient times, so a chromium spectral signature is a strong hint of a modern painting. And although chromium is not particularly rare, it wasn't particularly accessible in the west; the earliest known sources were in Siberia, making chrome pigments very expensive at first. Also, if a painting does use chrome yellow, and the yellow still looks yellow, it's probably recent; the color can degrade over time.
- Cobalt pigments: See smalt. Other cobalt pigments, such as cerulian blue (cobalt stannate, made from cobalt and tin compounds, which was made available in the 1860s), cobalt blue (Thénard's blue, copper aluminate, available from 1802), cobalt green cobalt zincate plus zinc oxide, with several shades depending on the mix), cobalt ultramarine (Gahn's Blue), cobalt violet (a name given to both cobalt arsenite and cobalt phosphate), and cobalt yellow (cobalt-potassium nitrate, known as aureolin, and first used in the 1850s), are too modern to appear in manuscripts.
- Emerald Green. Also known as vert Paul Véronèse because it resembled the
hues used by Paul Véronèse (the first painter said to have mixed pigments on his
palette rather than on the canvas) centuries before its invention. Also titled vert
de Schweinfurt after the place of its invention, and vert de Vienne and
vert de Brunswick, as well as Paris Green (this was a common name for it when used as an insecticide!).
This compound -- copper acetoarsenite -- is one of the best dating
hints available. It became available in 1814, and quickly became popular because it is
such a strong green (and was not very expensive). But it is also highly poisonous, and not particularly stable -- indeed, it could release arsenic into the air, making it
particularly dangerous. It
went out of use in the early twentieth century. So a painting which shows the traces
of this chemical was without doubt painted in the century after 1814.
Closely related to Emerald Green is Scheele Green, which is also a compound containing copper and arsenic. The famous chemist Carl Wilhelm Scheele discovered Scheele Green in 1778, and it became popular for a few decades -- popular enough that it has been speculated that it was responsible for the arsenic poisoning which may have killed Napoleon. Then Emerald Green was created by a modification of Scheele Green, and quickly displaced it. So a copper/arsenic spectrum indicates one of these two, both of which can be dated precisely, and if it can be determined whether the compound is Emerald Green or Scheele Green, it is possible to date it to within a few decades. - Fluorescents. The first flourescent dyes (that is, dyes that absorb ultraviolet light and reflect it as blue or other visible colors) became available in 1929. Thus anything with a fluourescent additive is recent.
- Gamboge. A yellow, the name being apparently a corruption of "Camboja," Cambodia. It is a tree resin from southeast Asia, which did not reach the west until after the manuscript era although it was in use much earlier in Asia. It fades very quickly. It was also mixed with Prussian Blue or indigo to form something called Hooker's Green (which is not the same as a modern Hooker's Green pigment).
- Iodine scarlet (and other iodine colors): Invented early after the discovery of iodine, they became commercially available in the early nineteenth century. Thus an iodine signature is clear evidence of a late painting. Iodine colors weren't used for very long, either; they are extremely chemically unstable, and paintings with them now look very different and decayed -- and painters learned this quickly and stopped using them.
- Lemon Yellow (and other barium pigments). Lemon Yellow is not really a single pigment; there were many different recipes -- but all involved barium compounds. It became a popular pigment due to its bold hue, but the earliest version was first created in 1809 and cannot be found in any ancient manuscript.
- Manganese pigments. Manganese forms compounds with blue and violet colors which have become popular -- but the first manganese pigment, manganese violet, was not produced until 1868 (others say 1890). Spectral evidence of manganese is therefore strong evidence of inauthenticity.
- Pastels. We think of "pastels" as soft colors, but the term was initially used for a type of coloring agent. Pastels (from Latin pastillus, a small block or loaf in the shape of a block) consist of a powdered pigment, a powdered white mineral, and a binder. They were invented in the sixteenth century (based on chalks), but it seems to have been many years before they became a common art form or before most colors became available (the earliest colors seem to have been white, red, and black). Thus, while it is just barely possible that a pastel might have been used to decorate a manuscript, if the number of shades is large, it is certain that the drawing is late.
- Phthalocyanine Green (and other phthalocyanines). This is a very recent pigment, first discovered in 1934 and first used in Europe apparently in 1938. I know of no instances of them being used in a Biblical forgery, but phthalocyanine green was used in the forged paintings in the Archimedes Palimpsest. It is said to resemble the color of viridian. Phthalocyanineblue, which came even later, is now used as a substitute for Prussian Blue.
- Pink. These days, we think of "pink" as a color name, but it used to be the name of a preparation -- a mix of an organic color, such as weld, with an inorganic powder carrier. So there were "yellow pinks," "green pinks," etc., with the current color name being derived from "rose pink" after the other pinks had gone out of use. But it appears the "pink" process was rare -- if indeed it was used at all -- before the sixteenth century, so if you can prove a product is a "pink" (which may be hard to do, given that most of the individual ingredients were older), it is a late drawing.
- Prussian Blue. This is a famous pigment for a variety of reasons (among other things,
it is the blue of blueprints), and has been used to detect many forgeries. It was one of the first synthetic pigments, and the first synthetic blue, first made available in the 1720s. It is called Prussian Blue because it was produced by Diebach, a Berlin experimenter (by accident; he was trying to produce a cochineal red, but he was cheap and bought some potash contaminated with oil, and the oil contaminated the mix. Having produced such a surprising color, he then had to experiment for some time to figure out just what he had done!). The result is a dark blue, almost blue-black. It's
not as pretty as some of the earlier natural blues, but the color is quite distinct.
The first Prussian blues were a mix of chemicals,
but the dominant component is a hexacyanoferrate.
Note the "cyano-" in that description. That's "cyano-" as in "cyanide." The key component of Prussian Blue is the cyanide ion CN-. Cyanide chemicals are, of course, highly poisonous (although Prussian Blue itself is not particularly dangerous), and there are no known natural sources for cyanide compounds of iron. The cyanide group is easily detected spectroscopically, and can only come from a cyanide pigment. Since there were none of these known before Prussian Blue, a cyanide spectrum in a pigment is a reliable indication of a late date.
It is ironic to note that Prussian Blue, made from poisonous components, is the antidote for another poison. A person suffering from thallium poisoning is given Prussian Blue, because the potassium in the dye will exchange with the thallium, restoring potassium balance and allowing the thallium to be eliminated from the body. - Scheele('s) Green: See emerald green.
- Smalt. A blue compound containing cobalt and potassium (said to have been made from
ground potassium glass mixed with cobalt), discovered in the late renaissance. Thus
it is just possible that it might be found in a fifteenth century manuscript -- but not an early one. (In fact, the use of a cobalt pigment was used to expose some fake Vermeers after World War II.) Since cobalt is quite similar to iron in behavior, and was not discovered until fairly recently, it is highly unlikely that any cobalt pigment other than smalt will be found in a manuscript. Nor is smalt a particularly good color for manuscript illuminations, since it has poor hiding power and is easily overwhelmed when mixed with other pigments; a more typical use was to color glass. Thus it seems to have been used only from the fifteenth century until the invention of Prussian Blue, which is similar in color but much stronger.
Smalt originally occurred naturally, as "cobalt bloom" (whence, supposedly, the name "cobalt"); this was quite a dangerous chemical, since it contained a significant amount of arsenic. This is another reason why true smalt is unlikely to be found in a manuscript.
Unfortunately, the word smalt is sometimes used to refer to other colors; some have claimed that the Egyptians used smalt (although it's not sure where they would have gotten the cobalt if they did; there is a mystery here which requires more investigation than it seems to have been given). Thus a reference to smalt, as opposed to the use of cobalt oxide and potassium silicate, is not indicative of date. - Strontium Yellow and other strontium pigments. A pigment very similar to lemon yellow (it is chemically much the same except for the substitution of strontium for barium), but it is a very recent invention and uses a rare element that would not easily be found naturally.
- Titanium White. Because it is fairly inexpensive, non-toxic, and a bright white, titanium dioxide (TiO2) has become a very popular modern pigment -- it is the replacement for white lead in house paint. But it is quite modern; although the mineral form rutile has been known in rocks for centuries, it is usually too impure to be useful in pigment. Titanium white paint was not sold until around the time of the World War I. Thus its use is a clear sign of forgery. We do seem to find rutile in the Göttingen copy of the Gutenberg Bible -- a finding which caused substantial surprise -- but finding a titanium signature in a pre-fifteenth-century manuscript is certainly grounds for suspicion.
- Zinc pigments. There are primarily two, zinc yellow and zinc white.
Zinc white (marketed in the nineteenth century as Chinese White), although known from
early times, does not seem to have been used as a pigment because it had limited
opacity and hiding power. It also was somewhat expensive -- and brittle, so that a section painted in zinc white could see the paint crack. Also, the color is considered to look colder than white lead, so as long as an artist could live with its toxicity and tendency to discolor, lead white was preferred.
Because the element zinc was well known to the ancients, it is barely possible that there might be a manuscript using zinc white -- but it is unlikely, both because zinc white was put into use later (first listed as a pigment in 1782 and first sold in 1834) and because it is not very opaque. Also, it dried slowly, so it was not a very useful pigment until someone discovered a chemical that made it dry faster. Although I would not consider a zinc spectral reading sufficient reason by itself to declare a painting a forgery, it is a very strong hint.
Zinc yellow, a zinc/chromium mix from the nineteenth which was not sold until the mid-nineteenth century, probably would be sufficient reason in itself to declare a forgery.
To put all this in perspective, a standard Impressionist paint palette of 20 colors included all of the following (those not known in ancient times marked *; those known only in the late Middle Ages marked **): *zinc white, lead white, *lemon yellow, *chrome yellow, *cadmium yellow, **Naples yellow, yellow ochre, *chrome orange, vermillion, red ochre, **madder lake, cochineal lake, *Scheele's green, *emerald green, *viridian, *chrome green, *cerulean blue, *cobalt blue, ultramarine (artificial), bone black. Thus, of these twenty, fully twelve were not available to manuscript painters. To be sure, the Impressionists generally weren't trying to fake Biblical manuscripts -- but the list shows how hard it would be to do if one weren't very careful. A nineteenth century fake, if it contains illustrations, will almost certainly be revealed by spectroscopy.
Nor is spectroscopy the only way to detect modern pigments. Even such a simple technique as microscopy can be quite useful -- e.g. it can detect the difference between ancient and modern ultramarine. In modern ultramarine, the lazurite particles are of a uniform size; in early ultramarine, no matter how carefully ground, there will be substantial variation in particle size.
Microscopy can sometimes give slight hints about the origin of a drawing, too, by giving us a look at contaminants (dust, etc.) in a painting -- e.g. there is sand stuck in the paint of some of Monet's beach scenes, so he presumably painted the pictures "on site."
Carbon Dating
The sciences have, over the last half century, given us many new ways to date early objects. The methods vary widely in both their accuracy and their side effects (e.g. electron spin resonance is largely non-destructive, but can be performed only once), but the earliest and the best-known remain the methods based on radioactive decay.
Ordinarily I'd go straight into the physics here, but in this case, I want to start with some information given to me by Tom Hennell, showing how carbon dating appears to have completely revolutionized our understanding of the Ethiopic version. I'll simply print his account, with my interventions marked in [].
Since the late 1960s, it has been commonly recognised that two Gospel manuscripts conserved in the remote monastery of Abba Garima witnessed the earliest recoverable form of the Ethiopic version of the New Testament. Otherwise however, although the translation of the Gospels into Ethiopic was believed to have been achieved in the Kingdom of Axum in the 4th/5th centuries, the oldest known gospel manuscript was dated between 1181 CE and 1221 CE. The Garima Gospels were clearly older than this, but the general judgment was that they could not be very much older; as the high quality and clear classical influences of their illuminated pages argued close contact with Eastern Roman culture, contacts that had only been re-established in Ethiopia with the emergence of the Zagwe dynasty in the 11th century. In 2001 Zuurmond could still state, "a gap of half a millennium exists between [the Ethipoic version's] origins and the earliest manuscripts."
Not everyone accepted this later date though; the monks maintained the pious legend that the two books had been written by Abba Garima himself; which if based in any way on truth, would have implied a sixth century date, as Abba Garima was said to have founded his monastery in 494 CE. Another dissident was Marilyn Heldman, who had published notes the gospels’ illuminations in 1987, pointing to the strong correspondence between the evangelist portraits of Matthew, Luke and John in the Garima Gospels, and the four carved evangelist portraits on the ‘Throne of Saint Mark” in Venice. This throne/reliquary was generally considered to be Alexandrian in origin, and to date from the 6th century.
In 2000, Jacques Mercier noticed[,] while examining the Gospels, that detached fragments of parchment from the illuminated pages were lodged amongst the leaves; and obtained permission to send two fragments to the Oxford Research Laboratory for Archaeology & the History of Art for carbon dating. The results came back with dates of 330-540 CE for a fragment more likely from Garima 2; and 430-650 CE for a fragment more likely from Garima 1. If true; these results might indeed confirm a sixth century date; but clearly there could still be uncertainty; perhaps the parchment fragments were from a different manuscript; perhaps the illuminated pages were much older than the text pages. Consequently, following restoration and rebinding of the two manuscripts, the carbon dating was repeated at the Research Laboratory for Archaeology & the History of Art in 2012, taking samples from both illuminated and text pages. This second exercise confirmed dates of 390-570 CE for Garima 2; and 530-660 CE for Garima 1.
From being a version with exceptionally late manuscript attestation, the Ethiopic over a few years has moved right amongst the versions with the earliest attestation -- at least for the Gospels. Previously, the earliest dated Christian illuminated manuscript anywhere had been the Rabbula Gospels of 586 CE; now Garima 2 heads the list (albeit that the yet undated Quedlinburg Itala fragments are most likely earlier). What is certain is that Garima 1 now stands as the oldest surviving book in the world still bound within its original covers.
If that doesn't demonstrate the importance of radioactive dating, I don't know what would!
The principle of radioactive dating is this: If you have a radioactive isotope, it decays at a fixed fractional rate rate. (If you don't know what an isotope is, see the section on isotope analysis.) If 20% of the original sample has decayed after a thousand years, then in the thousand years after that, 20% of what remains will have decayed (meaning that 36% will have decayed in that time), and 20% of the remainder after another thousand years (meaning that 48.8% will be gone, and 51.2% remaining). This is why we speak of radioactive half-lives: It is convenient to describe the time it takes for exactly half of a sample to decay.
The general formula for radioactive decay is
N = N0eγt
Where N0 is the number of atoms of the material you start with, N is the number you still have after time t, and γ is the so-called decay constant, a measure of the rate at which the isotope undergoes radioactive decay. A little algebraic manipulation will show that the half life h is therefore given by
h = -ln(0.5)/γ
Or equivalently that
γ=-ln(0.5)/h
(With appropriate units, of course.)
Note what this means: If you have a sample of something containing a radioactive element, and seal it up for some period, you can determine how long it was sealed by taking the ratio of the element and its by-products.
Alternately, if you have a sample which started with multiple isotopes of the same element, some stable and some radioactive, and you know the initial relative quantities of the isotopes, you can seal it up and wait for some years and again compare the ratios, and on this basis determine how much of the radioactive isotope has decayed, and on this basis you can determine how long it was sealed.
There are many of these "atomic clocks." A popular one is potassium-40 and argon-40. Potassium-40 has a half-life of 1.248x109 years -- that is, one and a quarter billion/milliard years. It is thus very good for dating ancient rocks, since even the oldest rocks still have a substantial fraction of their initial Potassium-40.
There are difficulties, however. Radioactive dating is only accurate to within about 5% of a half-life (sometimes more, sometimes less, depending on a lot of things including the size of the sample. Take it as a rule of thumb). For potassium-40, that means a dating error of ± 60 million years. That's no help dating a manuscript that was written some time between 100 C.E. and 1900 C.E.!
Hence the need for shorter clocks. The half-life of carbon-14 -- radiocarbon -- is 5715 years, or alternately γ is -0.000121. And that is a short enough period to allow useful datings of almost any product of human civilization -- it was used, for instance, to demonstrate the the Shroud of Turin was from the medieval era, not the New Testament era. 5% of 5715 years is about 275 years, so we can date any object made within the last 30,000 years or so with an accuracy of ± 150 years. Sometimes less than that, with the latest techniques and a sufficient amount of source material.
Carbon-14 is formed in the atmosphere when nitrogen-14 is hit by cosmic rays, causing one of the protons in the nitrogen atom to turn to carbon. The total carbon produced this way is estimated at seven killograms per year. That's not a huge amount, but at any given time it means that about 40 metric tons of carbon-14 is in circulation -- most of it as a chemical component of living things, where carbon is absolutely essential. And this is the only source of carbon-14; it cannot be found in rocks or anything that is not derived from the atmosphere, because all the carbon-14 inside the earth has long since decayed.
The key fact which follows from this is that plants and animals only soak up carbon-14 from the atmosphere, or from other living things, for as long as they are alive. Once they die, the carbon-14 supply is cut off. From then on, the quantity of carbon-14 can only decline, as individual atoms decay back into nitrogen.
The rest of the carbon in the dead material is non-radioactive. It sticks around forever. So the age of a particular organic material can be dated by comparing the ratio of carbon-14 atoms to the atoms of stable carbon-12 and carbon-13. (We should note that the original method was developed by Willard F. Libby, and that it won him the 1960 Nobel prize, although the refinements made since are in many ways more important than Libby's original invention.)
Unfortunately, for the most part, testing for carbon-14 requires destroying a sample. Fortunately, the tests have improved dramatically over the years, giving greater accuracy while requiring less material. Today, if the object is a few thousand years old or less, a mere sliver of material can give a date within a few hundred years. Older materials are harder to test, because the number of carbon-14 atoms will be very small; that's why the upper limit on dating is somewhere around 30,000 years, and even that probably would require more material than we would like to spare.
For all its limitations, carbon dating has the tremendous advantage of being a dating scheme that is objective and (relatively) repeatable. It seems to me that it would be a great boon to textual scholars if some of the more important manuscripts were tested and dated, giving us a check on paleographic dating.
And, once in a great while, it can be done non-destructively -- if the sample is of known chemical composition, so that the expected amount of carbon is known. If that is the case, it is sometimes possible simply to count radioactive decays to know the amount of carbon-14 in the sample. It's just that this cannot be relied upon.
For another look at some of the mathematics behind this, see the section on Arithmetic, Exponential, and Geometric Progressions in the article on Mathematics.
Spectroscopy
This is far too complex a subject to cover in detail, but it is a very powerful tool now becoming available to textual scholars. Behnam Sadeghi, for instance, was able to use the facilities at SLAC to determine much useful information about the copy of the Quran known as San'ã' 1.
To vastly oversimplify, spectroscopy consists of shining a light on something and seeing what reflects back (or, if it emits light by itself, looking at the nature of that light). All elements and compounds have their characteristic spectrum -- the wavelengths of light they absorb and emit.
The reason for this was not known at the time spectroscopy was discovered, but it turns out to have to do with the energy of electrons. The rules of quantum mechanics mean that an electron in an atom or molecule can possess only certain amounts of energy. It's like a ladder: You can only stand in the places where there are rungs. If the steps of the ladder are 20 centimeters apart, you can't go ten centimeters up the ladder -- there is no rung there. If you throw energy at an electron, it won't do anything until you give it enough energy to move a step up the ladder, at which point -- pop! -- it instantly moves up a rung. Since this stepping-up always requires the same amount of energy, the electrons of a pure chemical always absorb light of exactly the same color (since the color of light tells you just how much energy is in the photons that make up the light).
And electrons don't like to stay high on the ladder. They have a strong tendency, after being excited to the higher energy level, to give back the energy and return to the "ground" state. (The fact that physicists call it the "ground" state shows how close is the analogy to a ladder.) When it gives up the energy, the electron emits a photon of light which has exactly the amount of energy it absorbed to move up the ladder.
So, for instance, if you shine a white light (which contains photons of all energies) through a sample of sodium, the sodium will capture two different colors of yellow light and leave all the rest alone. If you scatter the white light through a prism, you will see a rainbow spectrum like this one:
But if, before you pass it through the prism, you expose the light to sodium, which absorbs two wavelengths of orangish-yellow light, you will instead see this:
Note the two dark lines in the yellow region. This is the light that has been absorbed by the sodium. That pair of dark lines is unique to sodium; if you see those bands in a sample of white light, you know it has been influenced by sodium.
Because every chemical has its unique spectrum, spectroscopy is an amazingly powerful tool. In the nineteenth century, e.g., it was used to identify the element helium in the sun -- an element which was not discovered on earth until later. In the early twentieth century, spectroscopy allowed us to discover the expansion of the universe. The spectroscope has proved one of the most important scientific tools in the history of chemistry and astronomy.
And that was with primitive spectroscopes. The equipment today is much better. We can (non-destructively) scan the ink used to write a manuscript. We can identify stains. With sufficiently high-quality equipment, we can even look at what lies under, say, a painting (this was done, e.g., with the Archimedes Palimsest).
Unless a manuscript is particularly important, it probably isn't worth going over every stain and smudge to determine its chemical composition -- especially since the stains may well be later than the manuscript. But testing the ink of the original scribe could be informative. If it shows a signature of an unusual chemical, it might help us localize the manuscript. We might also be able to work on the dating of various ink formulations.
Spectroscopy is also good at detecting forgeries, by looking at the materials in the ink on a document. (See the section on Paints and Pigments for how this has been used, e.g., with Prussian Blue.) These techniques are currently being used on the small fragment known as "The Gospel of Jesus's Wife," widely suspected of being a forgery, although as of this writing, the results have been inconclusive.
Among the new techniques of spectroscopy are:
- Energy-Dispersive X-ray analysis (EDX), a particularly powerful tool because of its ability to penetrate materials. It is based on wavelengths emitted.
- Fourier-Transform Infrared spectroscopy. It is based on wavelengths absorbed.
- Macro X-ray Fluorescence Spectrometry (MA-XRF), which uses X-rays to look through the bindings of books to read any texts found in the bindings without damaging the covers or opening them up.
Isotope Analysis
This is a relatively new technique for dating and (more importantly) locating manuscripts, although (like carbon dating) it is destructive.
As you probably know, an atom consists of a nucleus comprised of protons and neutrons (themselves made of quarks, but that need not detain us), circled by electrons. The electrons are what produces chemical behavior, and the number of protons in the nucleus determine how many electons an atom "wants" to have. So the number of protons in the nucleus determines the element to which the atom belongs.
The number of neutrons, as far as chemical behavior is concerned, is irrelevent. A carbon atom has six protons. Most carbon atoms have six neutrons as well, but we find atoms with seven neutrons, or even eight -- the version with eight neutrons is the carbon-14 used in carbon dating. Different atoms with the same number of protons but different numbers of neutrons are called isotopes, so-called because they're chemically the same but structurally different.
The number of neutrons does not affect the chemical behavior in any way. But neutrons have mass -- the isotope of carbon with six protons and six neutrons is lighter than the one with six protons and eight neutrons. This means that you can separate heavier from lighter isotopes. The typical method of doing this is the mass spectrograph or the centrifuge -- you take the atoms and, in effect, give them a push. The light ones will fly a little farther than the heavy ones. By counting how many go a long way, and how many travel only a relatively short distance, you can tell the ratio of heavy to light isotopes.
This is basically the method used to create nuclear weapons by separating U-235 (which is usable in bombs) from U-238 (which does not fission). However, separating U-235 from U-238 is not a very efficient process. In enriching uranium, centrifuges work on a compound known as uranium hexaflouride, UF6. The molecular mass of UF6 is 349 if it has an atom of U-235, 352 if it has an atom of U-238. That's less than a 1% difference, and the centrifuging is a slow process that must be done repeatedly to purify the U-235. (This is why it is so hard to get enough enriched uranium to make a bomb. Everyone knows the basic steps, but they are difficult to perform in practice.)
Isotope analysis is different. The usual method involves oxygen, particularly isotopes O-16 and O-18, often in molecules of water. A molecule of water with in which the oxygen atom is O-16 has a molecular mass of 18 units, one based on O-18 has a mass of 20 units -- a 10% difference. This is much, much easier to measure.
This technique is useful because climate affects the mix of isotopes. Water based on O-18 tends to sink lower than that based on O-16. The two may also form ice at different rates. Based on facts such as these, one can sometimes use isotope analysis to determine the date or location in which a material originated. I know this was used at least once to determine that the parchment in a manuscript came from the Mediterranean basin.
DNA Sequencing
DNA sequencing has now come so far that it would certainly be possible to use it to detect what sort of animal was used to produce parchment (sheep, cattle, other). It might, indeed, be able to determine where the the animal originally lived, or where the papyrus, or the linen used to produce paper, grew. I do not know of anyone using the techniques for that purpose, though.
There is another thing about DNA sequencing that perhaps has some significance to those who are reconstructing textual sequences. And this is the reconstructing of DNA sequences themselves.
To begin with, it is important to remember that DNA consists of a chain of four chemical "letters," which we abbreviate A C G T. I won't go into further detail on this; you can look it up in any elementary book on DNA. The point is that any DNA sequence will consist of a sequence of these letters, e.g.
| A | C | G | T | A | A | T | A | C | C | C | G | G | C | A | T | A | T | A | T | G |
But DNA is a complex molecule that needs maintenance. As soon as the cell containing it dies, it starts to go to pieces -- slowly, but inevitably. If you look at DNA from ancient cells, instead of getting one relatively long strand such as that shown above, you'll get many copies of fragments, e.g.
| 1. | A | T | A | C | C | C | G | G |
| 2. | G | C | A | T | A | T | A | T | G |
| 3. | C | C | C | G | G | C | A | T | A |
| 4. | T | A | C | C | C | G | G | C |
| 5. | A | C | G | T | A | A | T | A |
So how does one reconstruct the original DNA from these fragments? By starting with places where an unlikely pattern appears to recur. For instance, look at #3 and #4 and their sequence CCCGGC. It's a pretty good bet that these represent the same chunk of the original. So we line them up:
| 3. | C | C | C | G | G | C | A | T | A | |
| 4. | A | C | C | C | G | G | C |
Now look at the GCATA at the end of #3, and note the start of #2. So we combine again:
| 2. | G | C | A | T | A | T | A | T | G | ||||||
| 3. | C | C | C | G | G | C | A | T | A | ||||||
| 4. | T | A | C | C | C | G | G | C |
Now observe the TACCCG in the middle of #1, which aligns with the same in #4. So:
| 2. | G | C | A | T | A | T | A | T | G | |||||||
| 3. | C | C | C | G | G | C | A | T | A | |||||||
| 4. | T | A | C | C | C | G | G | C | ||||||||
| 1. | A | T | A | C | C | C | G | G |
This leaves us with segment #5. The leftmost part of it, the ACGTA, does not match anywhere. But we have three matches for the ATA at the end. It cannot match with the ATA in sequences 2 and 3, because the letters to the left are wrong. So it must line up with the ATA in #1, giving us this:
| 2. | G | C | A | T | A | T | A | T | G | ||||||||||||
| 3. | C | C | C | G | G | C | A | T | A | ||||||||||||
| 4. | T | A | C | C | C | G | G | C | |||||||||||||
| 1. | A | T | A | C | C | C | G | G | |||||||||||||
| 5. | A | C | G | T | A | A | T | A |
And with that we have reconstructed the entire original:
| Orig: | A | C | G | T | A | A | T | A | C | C | C | G | G | C | A | T | A | T | A | T | G |
| 2. | G | C | A | T | A | T | A | T | G | ||||||||||||
| 3. | C | C | C | G | G | C | A | T | A | ||||||||||||
| 4. | T | A | C | C | C | G | G | C | |||||||||||||
| 1. | A | T | A | C | C | C | G | G | |||||||||||||
| 5. | A | C | G | T | A | A | T | A |
In real DNA reconstruction, these segments are not long enough to give us a unique reconstruction; we would need longer fragments. (There are only 45=1024 possible sequences of five consecutive DNA bases, and tens of thousands of genes in most genomes, meaning that most five-base sequences will occur dozens of times in the whole genome. To reconstruct a gene typically takes sequences of fifteen or more bases. There is no exact cutoff for how ancient ancient DNA is before it ceases to be useful, but I have heard that the average DNA sequence for Richard III, which was recovered about 525 years after his death, was 45 bases. At that decay rate, we're looking at a few thousand years. But DNA in colder, drier places would last longer; DNA in wetter, warmer places would decay faster.) So you can't reconstruct DNA with segments of five to eight bases. But this shows the way the method works.
To be sure, there is another complication in DNA, which is that it has two strands, and the two strands are inverses -- for every A in one strand, there is a T in the other, and every C binds to a G, and so forth. So the DNA strand above was actually part of a pair like this:
| A | C | G | T | A | A | T | A | C | C | C | G | G | C | A | T | A | T | A | T | G |
| ⥌ | ⥌ | ⥌ | ⥌ | ⥌ | ⥌ | ⥌ | ⥌ | ⥌ | ⥌ | ⥌ | ⥌ | ⥌ | ⥌ | ⥌ | ⥌ | ⥌ | ⥌ | ⥌ | ⥌ | ⥌ |
| T | G | C | A | T | T | A | T | G | G | G | C | C | G | T | A | T | A | T | A | C |
And you can reconstruct using both strands simultaneously. But that's a complication we don't need to deal with for our purposes -- usually the two halves will be together, so that one strand can stand in for both. So we can treat two parallel strands as a single one.
This technique of piecing things together can equally well be used to reconstruct a text. It is obviously not necessary for the New Testament, where we have plenty of continuous texts to serve as a starting point, but it has some use (e.g.) for the Qumran texts. These sometimes exist in many but very fragmentary copies.
An interesting aspect of this sort of reconstruction in dealing with texts, as opposed to DNA, is that a fragment probably will not consist of only a single line but of parts of multiple lines -- and those lines will have a particular length.
Let's take as an example the first two sentences of Abraham Lincoln's Gettysburg Address. The full text is
Four score and seven years ago our fathers brought forth on this continent a new nation, conceived in liberty, and dedicated to the proposition that all men are created equal. Now we are engaged in a great civil war, testing whether that nation, or any nation so conceived and so dedicated, can long endure.
Now suppose we have a fragment of about a quarter of the above that wraps at about sixty characters. It might look like this:
Four score and seven years ago our fathers brought forth on
this continent a new nation, conceived in liberty, and
dedicated to the proposition that all men are created equal.
Now we are engaged in a great civil war, testing whether that
nation, or any nation so conceived and so dedicated, can long
endure.
Imagine another fragment, which wrapped at about fifty characters. It might look like this:
Four score and seven years ago our fathers brought
forth on this continent a new nation, conceived in
liberty, and dedicated to the proposition that all
men are created equal. Now we are engaged in a great
civil war, testing whether that nation, or any
nation so conceived and so dedicated, can long endure.
These two fragments are of course not enough to reconstruct the whole text. But because they are not enough, they show us some of the problems of reconstruction. Note, for instance, the phrase "whether that nation, or any nation so conceived." It will be obvious that there is a strong chance of h.t. errors when copying this, which might cause a few words to be lost -- and the loss is not easy to notice, because the sentence makes sense without the words "or any nation." And so, in trying to reconstruct from our fragments, it is vital that we try to keep track of the line counts! Only by that means can we tell how much space there should be between uses of the word "nation."
Detecting Forged Manuscripts
There are many ways in which a textual scholar can detect a forged manuscript. Not all are based on science, but some are. The list below attempts to catalog most of the more common methods available to a scientific manuscript detective:
- Carbon dating of the parchment. If the parchment is clearly newer than the claimed date of the manuscript, the manuscript is a forgery. Old parchment, of course, does not prove an early date, but it helps.
- Spectral imaging. If the illustrations, or even the ink, contain chemicals not known in the manuscript period, the manuscript is a forgery. The already-mentioned case of 2427 is an example. An even more amazing instance is the Archimedes Palimpsest, studied by J. L. Heiberg in the first decade of the twentieth century. It vanished after that, not to be restored to public view until the 1990s. At some time in that period, it had acquired four paintings -- completely irrelevant paintings, placed at absurd spots in the manuscript. (Reviel Netz and William Noel, in The Archimedes Palimpsest, speculate that the owner in 1940 was a Jew trapped in Nazi-occupied France, and made up the paintings to try to get the Nazis to preserve the book because it was "art." This explanation makes sense but cannot be proved; mostly what it shows is that the book should not have been in private hands!) The forged paintings, astonishingly, were recreations of illustrations in other manuscripts and were based on images published by Henri Omont in 1929 (Netz/Noel, p. 163).
- Other forms of imaging, such as X-ray, ultraviolet, and infrared can sometimes reveal artifacts not visible to the naked eye, although each has certain cautions (X-rays, having very high energy, can denature some pigments; ultraviolet images, which operate largely by flourescence, can't do much with varnished paintings, since varnish is flourescent; infrared has less resolving power). If the artifact is more recent than the purported date of the manuscript (say, a reference to a later historical event), then there is obviously a problem.
- Mistaken information which a contemporary scribe should have known. If a colophon contains too many historical oddities, it is a strong indication that the manuscript, or at least the colophon, is forged; 1505 is an example of this. Some care is required here, however: A also has a false colophon, but this is clearly a later addition, whereas the colophon of 1505 indicates that the manuscript was created as a forgery. And a colophon may sometimes be a copy of an earlier colophon that was legitimate in the source manuscript.
- Modifications of artwork. This is much more common in paintings, where a signature will sometimes be faked onto a piece to raise its value, but it might possibly happen in a manuscript as well. This can sometimes be detected by the nature of the paint -- an older portion of the drawing may become cracked, and the forgery may have paint spilling into the crack rather than being cracked along with the rest. Of course, we must be careful to distinguish between attempts at forgery and attempts at repair.
- Dating the binding. Many books (and paintings) have bindings of wood, and the wood can be dated by dendrochronology (tree rings). Of course, in this case, one must be absolutely certain that it is the original binding. The best use of dendrochronology is to give us a latest possible date for a book.
- Turpentine in illustrations. Turpentine as a painting medium, like oil, is a relatively recent invention. Although spirits of turpentine, derived from balsam (or pine, lrch, or fir) trees, was known since ancient times, the first real turpentine was not made until about the eighth century, and it does not seem to have been used in painting until about the time of the Renaissance. Thus if a manuscript uses turpentine paint, but claims to be from (to be very generous) the twelfth century or earlier, it is either a fake or has been over-painted.
Another point to keep in mind: Modern painters buy manufactured paints; they go to
art supply stores and buy a tube of Cerulian Blue or Cadmium Red or whatever. The squeeze
tube wasn't even invented until 1841; until that time, paints were usually stored in pig
bladders, and usually had to be used quickly before they dried out. During
the manuscript period, artists rarely were able to purchase finished paints.
At best, an apothecary would have the purified
source materials, which had to be mixed with a substrate. More often, the artist went
out and collected the materials himself, and ground and mixed them. Many of the
formulae were secrets, which the artist kept to himself or passed on only to his
apprentices. These early formulations will not be as consistent as modern pigments.
This has many implications which might be used to detect forgery apart from the
chemical hints above. But it also means that an artist had to be more than an artist. Which might help explain why some painters weren't that good at their craft. They might have had other skills which offset lack of true "talent."