Page 24 - Tibetan Thangka Painting Methodsand Mat, Jackson

The Preparation and Application of Size The Preparation and Application ofGesso
The preparation of size from the dried gelatin or To prepare the gesso the painter began by partially
hide glue simply consisted of soaking a piece of the filling a paint bowl with some of his finely ground dry
adhesive in water and then gently warming it. The size white pigment. He next poured in a little size solution,
was normally mixed in relatively small quantities - just stirring it in with a blunt-ended stirring stick (snur
enough to last for a day or two. When mixing it or skyogs). He then continued to add size, a little at a time,
reheating it the artist had only to take care that he did until the powder became the consistency of stiff dough.
not darken it by placing it over too hot a fire. Usually He carefully stirred and ground this mixture for some
he would warm it gently by placing its pot over a brazier time, using the pestle-shaped end of the stirring stick to
that contained a few hot coals. crush any lumps or pockets of dry pigment. When it had
The strength of the dried size varied a little from become thoroughly mixed he added a little more size,
batch to batch, but this made no difference to the and continued to stir. Sometimes he tilted the bowl to
painters, who always mixed their binders by "feel" the side and ran his stirring stick along the bottom to
and not by measure. In the absence of recipes, the make sure that all of the heavy lumps had been
artists performed simple tests to judge the strength of pulverized. Finally, he added just enough size solution
the size. For example, some painters would rub a little to bring the gesso to the consistency of buttermilk -
between the thumb and index finger, and then quickly the preferred consistency not only for gesso but also for
press together and pull apart the finger and thumb paints in general. This mixture was then strained through
several times. As they did so, the water evaporated from a cloth to eliminate any remaining lumps or bits of solid
the size and the strength of the solution became matter.
apparent: the tackier the size, the more the finger and As usual, the Tibetan painter did not use measures
thumb stuck together. Also, when accustomed to the when preparing gesso. Nevertheless, when questioned,
same type of size or glue, an artist could tell something one artist estimated that he used approximately two
of its strength just from its odor. parts of ka rag to one part of size solution. There was a
After the size had been evenly applied to both the certain amount of leeway in how strong the size had to
front and back of the painting and the fabric had been be. Some artists said that for gesso the size should be
tightened again, the painter set the stretcher aside and almost twice the strength of the ordinary size solution.
allowed the cloth to dry completely. Most artists pre- But others employed a size of about the same strength
ferred to dry it slowly, and many advised against putting as they used for sizing the cloth and for mixing ordinary
the newly sized fabric into hot direct sunlight. They paints.
usually dried their sized canvases either inside or in a To apply the gesso to the cloth, our main
shady spot out of doors. informants used a wadded-up rag or a gesso knife ('dam
khri). Some other artists also used oversized brushes.
Preparing the Ground Whichever applicator was used, the gesso had to be
applied in thin, even coats to both sides of the stretched
Once the cotton support had been stretched and 'sized, cloth. Wangdrak, who used a gesso knife, applied the
there only remained the application of a layer of gesso gesso sparingly, using the rounded tip of the knife like a
and its polishing to complete the preparation of the spatula, and being careful to scrape off the excess gesso
ground. When properly applied and finished this layer and leave a clean, smooth surface. The artist Legdrup
of gesso united with the underlying cloth, presenting Gyatsho, one of those who applied the gesso with a rag,
the painter with a surface that was excellent for both smoothed it while it was still wet and worked it into the
sketching and painting. support by rubbing the surface with the heel of his
hand. With his hand he also wiped off the excess. After-
Gesso ('dam)
wards, when the cloth support had become saturated
The "gesso" used by Tibetan painters was simply with gesso, both artists again tightened the strings
a mixture of the most available white earth pigment - around the stretcher frame, making the canvas taut and
either a chalk or a white clay (kaolin) - added to some flat.
size solution. s The usual Tibetan name for their white Next, when the first coat of gesso on both sides
earth colour was ka rag, although it was also known as of the cloth had dried, the artist had to determine
sa dkar ("white earth") or dkar rtsi ("whitewash"). whether a single coat had provided enough coverage.
Where whites of the best quality were scarce, any local He would hold the canvas up to a source of light and if
whitish earth could be substituted, providing that it had he could see many "pin holes" onight he knew that he
been properly washed, ground, and filtered through a had to apply another coat.
cloth. 9 Care had to be taken in obtaining the correct
After a coat of this gesso the white cotton support proportion of pigment to size. Too much size in the
became even whiter. It should also be noted that some mixture resulted in a hard and brittle canvas which
painters, particularly those from Eastern Tibet, preferred might crack and also cause flaking of the colours applied
a gesso that had a slightly ochreish hue. To achieve this over it, due to not enough 'grip' in the excessively sized
they added a small amount of ochre or yellow pigment surface. Not enough size in the mixture could also cause
to the gesso. 1 a flaking and powdering, especially when the thangka has

20 THE PREPARATION OF THE PAINTED SURFACE