LAMPBLACK

In the Middle Ages it was made by allowing a flame to play on a cold surface and collecting the soot which the flame deposited; sometimes a beeswax candle, sometimes tallow. Sometimes it was the flame of a lamp burning linseed, hempseed or olive oil; or by burning pitch or incense. It does made a difference as to what the source of the flame is as the black itself is pure carbon, but there are apt to be unburnt particles which may affect the color and working properties of the pigment. It was often used for ink making as it has an extremely fine grain and doesn't need grinding, and only needs to be mixed with a little gum water to make what we call, India ink. Our black inks made by a process which keeps the carbon permanently in suspension, was not known in the Middle Ages. Chinese stick inks are generally make with lampblack and gum; they are made for brush writing or painting on very absorbent surfaces, and often contain a larger proportion of gum than the medieval European carbon inks. It is supposed that these carbon inks, like the lampblack pigment, are absolutely permanent; we know that pure carbon black will never fade, but the material with which the ink was bound has often perished or become brittle, thus the writing has consequently been wholly or partially lost. The surface of parchment is so hard and close grained that even the fine grains of lampblack may fail to penetrate it if the lampblack is suspended in a strong solution of gum. Often they combined iron inks with carbon for denser black, which rendered it less permanent, however this would temper it for painting purposes. However, when mixed with water or water media, it becomes so light that the powder floats in the air and is not very manageable; tends to be a bit greasy; and though an excellent pure black, apt to muddy a bit in mixtures. Thus its value in history, was much more for ink-making than as a painting pigment.

LEAD TIN YELLOW

Although lead-tin yellow was used often in European painting before the eighteenth century, there is little evidence of its use from the older literature on painting techniques. The earliest recipe for a yellow pigment from lead and tin was found in a Bolognese manuscript from the first half of the fifteenth century, which mentions giallolino: a yellow of pale color, mentioned in Italian texts as identical to massicot of the northern manuscripts. Although lead-tin yellow was used in European painting before 1750, it was not really used after that time. There is no reference to a yellow pigment consisting of lead-tin oxide in the whole literature on color from the nineteenth century until 1940, when it was rediscovered by Jacobi at the Doerner Institute in Munich where he was doing investigations of samples from paintings, and subsequently it was synthesized in the laboratory.

LEAD WHITE

Also known as flake white, cremnitz white, kerms white, Berlin white, silver white, slate white and the list continues. The best quality is called cremnitz. As the name lead white suggests, it is a by-product of lead, and whatever the form of manufacture used, the purity of the color depends on the purity of the lead. Purifying processes greatly increase the cost of the product. White lead has always been one of the most important pigments in many painting techniques; yet chemists are still undecided as to just what our normal modern lead white is. In comparison to what the product was in the Middle Ages, that is. We have intensive recipes from that period, however the traditional method is as follows: the stack process. The "stack" consists of hundreds or thousands of earthenware pots containing vinegar and lead, embedded in fermenting tanbark or dung. They are shaped in a way that the vinegar and lead are separate, but the lead is still exposed to the vapors of the vinegar, by being coiled into a spiral which stands on a ledge inside the pot, above the well of vinegar in the bottom. It is then loosely covered with a grid of lead, which keeps the tan from falling in, allowing the carbon dioxide formed by the fermenting of the tan to enter the pot and act upon the coils and plates of lead with the vapors of vinegar and moisture.

A thick layer of tan is spread out on the ground: the bottom of the pit, and the pots with lead and vinegar are arranged upon it, covered with their leaden grids. More tan is laid over them and then usually a loose flooring of boards, followed by more pots, more tan, and so on until all the pots are imbedded. The temperature process: old tan partly used up, in certain proportions will continue to maintain proper heat. The heat, moisture, acetic acid vapor and carbon dioxide do their work for a month or so, and the stacks are dismantled. The metallic lead by this point has been largely converted into a crust of white lead on the coils and grid. These are then separated from the unconverted metal and washed free of acid and soluble salts, and ground for future use in painting. This stage of the work is simple but dangerous, for lead is a poison that builds up an incurable case of lead poisoning by breathing in a little of the dust of white lead, day after day, over time. Once it gets into the human system, it stays there until the body's tolerance level is met, and then becomes symptomatic. Medieval writers warn against the dangers of apoplexy, epilepsy, and paralysis, that come with exposure to it. What we don't know about the process of making white lead, is whether the final product is a definite compound or an accidental mixture. Regardless, its importance has been unmeasurable, and is the only material that has been consistently used from ancient times until the present.

The monopoly in lead white production was not broken until the nineteenth century, when zinc oxide became a competitor, and in the twentieth century, it has been almost completely replaced by titanium dioxide, which is superior to lead in some properties, and unlike zinc oxide, has the strong covering ability that lead white possesses. Since white in painting is the equivalent of light in nature, it has been essential to every aspect of painting: from flesh to skies, and so on. Because of its capacity to absorb x-rays, it is the lad white in European paintings that makes them visible through x-rays. It was also used on occasion in wall painting, tempera works on paper, and silk in early periods in China and Japan, even though lime white reproduced from calcination of the shells of mollusks had a wide use there. Leonardo Da Vinci, 1493: "Put the white into an earthen pot, and lay it no thicker than a string, and let it stand in the sun undisturbed for 2 days; and in the morning when the sun has dried off the night dew."

LITHARGE

This pigment is Massicot; the monoxide of lead described by Leonardo da Vinci. It is the heaviest pigment, slightly orange in color, and forms a cement which is impervious to water when mixed with Linseed oil. To form an actual cement, it is mixed with glycerine. It makes a drier known as lead drier when cooked at over 500 degrees F and mixed with Linseed (this is the lowest temperature in which it becomes soluble).

LITHOL RED

A similar color to Para red which does not bleed quite as much. It can't compare in permanance to many of the other reds such as Cadmium Vermilion, so therefore it is not terribly useful.

LITHOPHONE

Considered to be a very important pigment in the earlier part of this century: it is 30% Zinc sulphide and 70% precipitated Barium Sulphate, and was the basis of most wall paints from the turn of the century until the 1940s. Until the 30s it was not considered safe, as it turned dark in sunlight, and then turned white again at night. This quality was rectified by using pure chemicals in its' manufacture, though I wonder today how these faults could be manipulated if the fugitive chemicals could be duplicated?