Top 10 Composition of Pigments in the Tibetan paintings

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The application of colour to the thangka canvas involved two main steps first, filling in the areas of different base colours, and second, the subsequent shading and outlining of those areas.

To these steps there corresponded the two essentially different types of paint in the Tibetan palette

• Mineral pigments (rdo tshon and sa tshon) and
• The organic dyes or lakes (tshos)

The mineral pigments had to be mixed with a binder before being applied as paints. The chief binder for these pigments was size or hide glue, the same gelatinous solution that was used in preparing the “gesso” for the ground. Paints prepared in this way were used for the initial coat of colours. For the subsequent shading and outlining. However, the artists, for the most part, used dyes and lakes.

These needed little or no binder to unite them with the underlying layers of paint, and they could modify the hues and sharpen the borders of the painted areas without adding appreciably to the thickness of the paint layer.

The Classification of Thangkas by Colour

The use of colour could vary tremendously from one thangka to another. The number and types of colours used were in fact one set of criteria by which Tibetans traditionally classified thangkas.

Painted thangkas can be divided in the first place according to whether all colours were used or whether just one colour prevailed.

Most thangkas fell into the first group, the “full-colour” paintings in which the full palette was employed. The second group consisted of paintings in which one colour predominated and a few other colours were used in restricted roles.

Paintings that employed limited palettes could be further divided into three main sub-classes according to the predominating color black thangkas (nag thang or thang nag), gold thangkas (gser thang) and vermilion thangkas (mtshal thang).

The black thangkas were more common, being used especially for depicting fierce deities, whereas the gold and vermilion paintings were much rarer, and nowadays one almost never sees these types being painted.

The palette used by Tibetan artists when painting full-color thangkas were quite rich. It included pigments that in an unmixed state yielded all of the primary and secondary colors except purple. Also included were black and white.

Mineral Colours

The first two colors used by Tibetan artists in an ordinary full-palette thangka were the mineral blues and greens. The choice of these pigments as the first to be applied, and the fact that they were initially used to paint the sky and landscape, were determined by principles of efficiency in painting technique, and not by religious or other considerations.

Azurite Blue (mthing mdo mthing)

The pigment used for sky, water, and other blue areas was azurite, the blue basic carbonate of copper, 2CuC0₃Cu(OH)₂. Azurite occurs in nature as beautiful monoclinic crystals as well as in massive and earthy forms.

The main source of this mineral in Tibet was Snye-mo-thang in Gtsang, north of the Gtsang-po near the border of Dbus. Because of its importance in painting, the Lhasa government strictly controlled the mining and primary distribution of the pigment, so that artists usually got it directly or indirectly from a government office.

Besides being mentioned in some Tibetan sources on painting materials, azurite is discussed in Tibetan pharrnacopeias, for it was used as a medicine in the Tibetan Ayurvedic system of medical practice.

Malachite Green (spang ma mdo spang)

After azurite blue, the next pigment to be applied was the green derived from the closely related mineral malachite, the basic carbonate of copper, CuC0₃Cu(OH)₂.

As noted above malachite and azurite generally occur together in Tibet, both minerals were in fact extracted from the same deposits in Snye-mo-thang. Malachite is also mentioned in the pharmacopeias of Tibet, where it had the additional names spang tshon and tshon Ijang.

The azurite and malachite from Snye-mo-thang came in a crushed, sandy form, wrapped in small leather bags. One painter informed us that up to three different colours were available from this source in addition to the usual azurite blue and malachite green, he could sometimes also get a deep blue-green colour called g.yu kha.

Before they could use these colours as paints the artists had to clean and grind the crude pigments, and then separate several values of colour from each basic mineral. As a rule, they had to begin by cleaning the minerals by repeated scrubbing and rinsing.

To start with, an artist (or an assistant in charge of preparing colours) will follow these steps:

• Poured the material into a container of warm water and stirred it briskly.
• After allowing the mixture to settle for a few moments, poured off the surface foam together with the dirty water-bearing undesirable dust and earthy impurities in suspension.
• Add a little glue, and proceeded to knead and rub the earthy mixture between his hands.
• Next, again add warm water, and having stirred it up he allowed it to settle and then poured off the dirty water as before.
• Repeat this process until the water poured off was clean, at which time he could transfer the mineral to the mortar for grinding.

The mortar (gtun khungJ and pestle (gtun) were usually simple implements made from stone, the mortar being a shallow stone dish large enough to accommodate quantities of mineral pigment, and the pestle a hard elongated stone with smooth rounded surfaces.

If large amounts of mineral pigments had to be ground, for instance, while painting the murals of a large temple, the workers sometimes suspended a stone pestle just above the surface of the mortar by ropes.

Due to the elasticity of the ropes, the pestle could be brought to bear on the surface of the mortar by lightly pressing down on it, and in this way, the workers could grind pigments for long periods of time with a minimum of exertion.

Azurite and malachite, unlike some other pigments, were subjected to “wet grinding” (rlon rdul), and for this, the painter would add some water to the already damp, earthy mass in the mortar before he began grinding.

In their crude state the mineral pigments were dull and unattractive, but after cleaning and just a little grinding the deep rich colors appeared.

The actual grinding of the pigments proceeded in a steady, smooth way. It was not necessary to grind azurite or malachite to an extremely fine powder. In fact, it was better to grind them too little than too much. Unlike lapis lazuli (another mineral yielding a deep blue that was used outside Tibet), azurite and malachite become progressively whiter and paler the more finely they are ground. If ground as finely as most pigments are, they lose their original deep colours almost completely.

This special property of the copper carbonate minerals was a reason for caution during grinding, but it also made possible a simple method for deriving several shades of colour from each mineral.

Grinding reduced the original crude pigment into particles ranging in size from fine sand to very fine dust. Because different values of color corresponding to the different sizes of particles, several lighter and – darker values of green and blue could be extracted through progressive sedimentation.

First, the artist stirred up the ground mineral in the water. When most of the heavier, darker particles had settled to the bottom, the artist poured the water and the lighter particles still in suspension into a separate dish.

The process could be repeated with both the lighter shades and the darker, heavier remains so that from one mineral at least four distinct shades could be derived, each known by its own name.

The first, lightest suspension of azurite was known as sngo in the next, sky-blue suspension as sngo sang the third, medium blue as mthing shul and the deep azu re coarsest suspension as the thing. Similarly, the four gradations of malachite were, from lightest to darkest, spang si. spang skya. spang and spang smug.

In Tibet, these two minerals were not extremely expensive per unit of weight. But because they were used in great quantities over large areas of sky, meadows and other parts of the paintings and since they had to be applied in relatively thick coats to produce the deeper colours, they accounted for a large part of the painter’s expenses.

Among the various shades of the two pigments, the bright green malachite was said to be the most expensive. And in general, nearly twice as much malachite as azurite was used.

Lapis Lazuli (mu men) and Ultramarine

In the past, some Western writers have asserted that lapis lazuli, the deep blue semi-precious stone, was the source of the blue pigment commonly used by Tibetan artists.

Lapis, being a color similar to azurite, has frequently been confused with azurite in other times and places. The dark blue constituent of lapis lazuli is the mineral lazurite (sodium aluminum silicate, with sulfur), whose very name reveals a common etymological origin with azurite.

Lazurite, however, is much rarer than azurite. Only a few major deposits are known in the world, the largest of which is in Badakhshan in Northeast Afghanistan. Therefore, even though lazurite was sometimes used as a pigment it was usually far more costly than azurite. In medieval Europe, for example, the precious pigment ultramarine (powdered lazurite) was a weight for weight as costly as gold, and in those days ultramarine was commonly adulterated with the cheaper azurite.

Tibetans certainly knew of lapis lazuli. Although it was not normally used as a pigment, it was a well-known semi-precious stone, and the Ayurvedic doctors of Tibet considered it a medicinal substance. Jam-dpalrdo-rje in his Tibeto-Mongolian materia medica classified lapis lazuli (mu men) as a non-melting precious substance (mi bzhu baY rin po che), stating that it was a mineral found in rocky mountains.

In medicine, at least, the variety with gold specks (pyrite) was considered best, while the plain dark blue type with no specks was less desirable.

Lapis and azurite in their mineral forms could be easily differentiated. In addition to the characteristic golden specks, lapis also commonly had veins and specks of related white sodalite minerals.

Azurite, on the other hand, usually contained at least traces of the green malachite, and in a larger lump or rock, the two minerals often merged imperceptibly into each other. Modern Tibetan painters were well aware of the difference between the two blue minerals, and when questioned they unanimously declared that they had never seen lapis lazuli used as a pigment.

Artificial Ultramarine

In Europe, the pigment made from lapis lazuli has always been costly since only a small percentage of the lapis ore itself a valuable commodity could be converted into a usable pigment of the best quality. However, for years European alkali makers had noticed the occasional formation in their ovens of blue masses resembling ultramarine.

From this clue, and spurred on by a sizable monetary prize, a French chemist in the late l820s finally discovered the process for synthesizing ultramarine from such common materials as china clay, sulfur, and charcoal.

By the 1830s French and German factories were producing the pigment in large quantities. Having both a low price and the desirable qualities of the precious natural lazurite, the artificial ultramarine soon became for European painters the deep-blue pigment par excellence, and in Europe, it effectively put an end to the use of both lapis and azurite.

Other Synthetic Green and Blue Pigments

Emerald green is copper acetoarsenite, an artificial pigment first synthesized in 1814. It is not commonly identified in European paintings, and thus it is surprising to find it in these thangkas.

In addition to emerald green on the “Indian-style” painting the synthetic pigment Scheele’s green (copper hydro-arsenite), a similar pigment first prepared in 1788 that was widely used in Europe for only a brief period during the late 18th and early 19th centuries.

Here again, the presence of such artificial pigments allows the art historian to establish a terminus a quo in dating them. These works, for instance, could not have been painted much earlier than 1820 if these analyses are correct. Perhaps further investigations of Tibetan pigments will uncover the presence of even more synthetic pigments in thangkas painted in the 19th and 20th centuries, particularly in works from Gtsang.

The painter Wangdrak informed us that in the artistic traditions (lag rgyun) of Shigatse and its cultural satellites such as Lhatse, Gyangtse and Ngamring the colours imported from India through Darjeeling and Kalimpong actually predominated among artists for a time.

Although these colours began to lose some popularity in the 1930s, merchants who specialized in selling imported pigments continued to do business at the seasonal trade fairs and in the main towns of Gtsang.

Finally, some synthetic blue and green pigments from China also found their way into Tibet, especially in the eastern districts, Khams and A-mdo.

Sum-pa mkhan-po, writing on methods and materials of art, mentioned a Chinese green (rgya ljang = verdigris), and to this Mi-pham-rgya-mtsho added a mention of a Chinese blue (rgya mthing). Unlike the Tibetan blue and green (bod mthing, bod ljang), i.e. azurite and malachite, which were ground in plain water, the artificial Chinese pigments were said to need grinding with size solution (a spy in chu).

Cinnabar (cog la ma) and Vennilion (mtshal)

For their brightest reds, Tibetan artists used both native mercury sulfide – the mineral cinnabar – and the same pigment synthetically produced.

The mineral is known as cog-la-ma (cinnabar) or mtshal-rgod (“native vermilion”) in Tibetan, and it is said to occur in some parts of Tibet, for instance in the Southeastern region Lho-brag.

Most of the cinnabar or vermilion used in Tibet, however, came from China and India, and for this reason, it was also called rgya-mtshal (“Chinese or Indian vermilion”).

At Chen-chou in Hunan Province in China, for instance, cinnabar was mined in particularly abundant quantities; indeed, these min.es were probably the ultimate source of much of the cinnabar used by Tibetan artists. When ground into a fine powder suitable for painting, cinnabar was known to the Tibetans simply as vermilion: mtshal.

Cinnabar is the principal ore from which mercury is produced. Once the mercury has been separated from the sulfur content of cinnabar by heating, it is still possible to recombine it with sulfur.

Ordinarily, the combination of mercury with sulfur yields the black mercuric sulfide. But by carefully controlled heating and cooting, mercury and sulfur can be combined to produce the silver and red metallic crystals of artificial cinnabar.

As early as the 2nd century AD this transmutation of liquid mercury to crystalline cinnabar and back again was discovered and studied by Chinese alchemists, who considered these chemical reactions to be of fundamental importance since they so vividly displayed the transmutation of the elements, and above all since the changes were reversible. The process of synthesis was also known in ancient India, and both India and China became exporters of synthetic cinnabar and vermilion to Tibet.

Subsequently, the technology also spread to Tibet. Authors of later Tibetan pharmacopeias, for instance, describe the technique. In Tibetan medicine cinnabar or native vermilion was classified as a “meltable mineral medicine” (bzhu ba’i rdo sman), while the synthetic cinnabar, called da chu, was classified as a “manufactured salt” (bzo tshwa). Another name for the synthetic cinnabar was “white vermilion” (mtshal dkar), perhaps because of the silver glint of the manmade crystals.

Minium Orange (li khri)

For their main orange pigment, Tibetan painters used minium, the synthetic tetraoxide of lead. This pigment is also known as “red lead,” but the varieties used by Tibetan painters were actually intense orange, and not red or scarlet. Tibet did not produce its own minium, but imported it from Nepal and China. Minium was also produced in India the author of one Tibetan materia medica mentioned varieties of Indian minium that were produced from the earth, stone, and plants.

3D But the writers of such texts were also aware that the miniurns of China and Nepal were made from lead, in spite of the fact that they classified these as “naturally occurring earth medicines” (rang ‘byung ba’i sa sman).  For painting in particular, our main informants considered the synthetic miniums of Nepal to be the best.

Orpiment Yellow (ba bla) and Realgar (ldong ros)

The chief yellow pigment of Tibetan painters was orpiment, a natural yellow trisulfide of arsenic, As₂S₃ Deposits of orpiment occur near the surface of the earth, especially near hot springs or in the vicinity of silver deposits. In Tibet, the most famous deposits were found in East Tibet, near Chamdo. Large quantities of orpiment are also said to have been mined at Shihhaung-Ch’ang in Yunnan Province in China.

Yellow Ochre (ngang pa)

Yellow ochre is a fine-grained earthy variety of the mineral limonite, a hydrated ferric oxide. Although ochres have been popular among Western artists for some centuries, Tibetan thangka painters seldom used them as pigments in their own right, preferring the more intense yellow of orpiment. Nevertheless, yellow ochre was widely used as the main undercoat for gold.

Earth White (ka rag)

The main white pigments in Tibet were calcium compounds. The most common white was a mineral called ka rag, which seems to have been a high-grade white chalk. Like limestone and marble, chalk is basically calcium carbonate, but chalk is not to be confused with lime (rdo zho or rdo thai), the white oxide of calcium that is made by heating limestone in a kiln.

Carbon Black (snag tsha)

The blacks used as paints in Tibet were made from carbonaceous materials, and the sources – soot and black ash – were common almost everywhere in one form or another. Since carbon is chemically very inert, it was the basis for permanent, excellent pigments.

Gold (gser)

Gold, a substance recognized almost universally as a symbol of wealth and beauty, was highly prized as a pigment by both artists and patrons in Tibet. Pure gold not only possesses its own inimitable color and luster, but also it does not tarnish and it is extremely workable. It can be drawn into very fine wires, or it can be beaten so thin that light can pass through it. Such qualities lend themselves very well to the purposes of an artisan, for even when applied in very thin layers the reflective metal imparts to any surface the luster and beauty of solid gold.