Page 83 - Tibetan Thangka Painting Methodsand Mat, Jackson

In the past some Western writers have asserted that lapis effectively put an end to the use of both lapis and
lazuli, the deep blue semi-precious stone, was the source azurite.
of the blue pigment commoply used by Tibetan This new technology was of significance for
artists. 10 Lapis, being a colour similar to azurite, has Tibetan painting because pigments were highly prized
frequently been confused with azurite in other times commodities among Tibetans. Pigments and dyes had
and places. The dark blue constituent of lapis lazuli been common articles of trade for centuries, and at
is the mineral lazurite (sodium aluminum silicate, with times some were even used to pay taxes or tribute. 13 By
sulfur), whose very name reveals a common etymo- the present century, and perhaps" as early as the
logical origin with azurite. Lazurite, however, is much mid-19th century, synthetic pigments were finding their
rarer than azurite. Only a few major deposits are known way into Tibet via British India, and synthetic ultra-
in the world, the largest of which is in Badakhshan in marine may have been among these. Microscopic
Northeast Afghanistan. Therefore, even though lazurite analyses of pigments used in a sampling of eight
was sometimes used as a pigment it was usually far more thangkas have indicated the presence of ultramarine
costly than azurite. In medieval Europe, for example, in two paintings that also contained azurite and mala-
the precious pigment ultramarine (powdered lazurite) chite. 14 V. R. Mehra, the author of that study,
was weight for weight as costly as gold, and in those described one of the paintings containing ultramarine as
days ultramarine was commonly adulterated with the "lhasa style" and the other as belonging to the "sNar-
cheaper azurite. thang school." Presumably on the basis of style, these
Tibetans certainly knew of lapis lazuli. Although thangkas had been dated to the 18th or early 19th
it was not normally used as a pigment, it was a well century and to the early 17th century respectively.
known semi-precious stone, and the Ayurvedic doctors Without inscriptions or similar evidence one cannot
of Tibet considered it a medicinal substance. 'Jam-dpal- date such thangkas except in a very approximate way,
rdo-rje in his Tibeto-Mongolian materia medica classified but the finding of ultramarine in the paintings (if indeed
lapis lazuli (mu men) as a non-melting precious it was synthetic ultramarine) is a sure indication that
substance (mi bzhu baY rin po che), stating that it was a they date back to no earlier than about 1830.
mineral found in rocky mountains. 11 In medicine, at Unfortunately, Mehra did not indicate whether the
least, the variety with gold specks (pyrite) was con- "ultramarine" was natural or man-made, although
sidered best, while the plain dark blue type with no under a microscope it is easy to differentiate between
specks was less desirable. the two. 15 If the presence of synthetic ultramarine
Lapis and azurite in their mineral forms could be can indeed be verified by both visual and chemical
easily differentiated. In addition to the characteristic tests, the art historian will be supplied with a valuable
golden specks, lapis also commonly had veins and specks bit of evidence for the scientific dating of works con-
of related white sodalite minerals. Azurite, on the other taining it.
hand, usually contained at least traces of the green
malachite, and in a larger lump or rock the two minerals Other Synthetic Green and Blue Pigments
often merged imperceptibly into each other. Modern
Tibetan painters were well aware of the difference Curiously, Mehra's analyses also indicated the presence
between the two blue minerals, and when questioned of an "emerald green" on two thangkas, one being the
they unanimously declared that they had never seen "lhasa-style" painting of the "18th or early 19th
lapis lazuli used as a pigment. century," and the other being described as "Indian style,
early 19th century." 16 Emerald green is copper aceto-
arsenite, an artificial pigment first synthesized in
Artificial Ultramarine 17
]814. It is not commonly identified in European
paintings, and thus it is surprising to find it in these
In Europe the pigment made from lapis lazuli has always thangkas. In addition to emerald green, Mehra also
been costly since only a small percentage of the lapis ore identified on the "Indian-style" painting the synthetic
- itself a valuable commodity - could be converted into pigment Scheele's green (copper hydro-arsenite), a
a usable pigment of the best quality. However, for years similar pigment first prepared in 1788 that was widely
European alkali makers had noticed the occasional used in Europe for only a brief period during the late
formation in their ovens of blue masses resembling 18th and early 19th centuries. 18 Here again, the
ultramarine. From this clue, and spurred on by a sizable presence of such artificial pigments allows the art
monetary prize, a French chemist in the late l820s historian to establish a terminus a quo in dating them.
finally discovered the process for synthesizing ultra- These works, for instance, could not have been painted
marine from such common materials as china clay, sulfur much earlier than 1820 if these analyses are correct.
and charcoal. By the 1830s French and German Perhaps further investigations of Tibetan pigments
factories were producing the pigment in large quan- will uncover the presence of even more synthetic
tities. 12 Having both a low price and the desirable quali- pigments in thangkas painted in the 19th and 20th
ties of the precious natural lazurite, the artificial centuries, particularly in works from Gtsang. The
ultramarine soon became for European painters the painter Wangdrak informed us that in the artistic
deep-blue pigment par excellence, and in Europe it traditions (lag rgyun) of Shigatse and its cultural

MINERAL COLOURS 79