Picchwai – gilded Indian textile

Background

Picchwais are large paintings on cloth relating to the worship of Krishna. They were commissioned for temples and shrines, often for specific festivals, and hang behind the altar. This picchwai celebrates the festival of Gopashtami, the festival of cows, and represents a significant day for worshippers of Krishna, marking the day in which Krishna is elevated from a herder of calves to a fully-fledged cowherd.

This picchwai was made using a waraq printing technique, a process wherein gold or silver leaf is applied on to the textile through a transfer technique using blocks. A base layer, typically roghan paste made from linseed oil mixed with chalk and sometimes pigments, would be stamped on the fabric using blocks. The waraq (leaf) was then applied while the gum was moist. Over the top of the waraq, and directly on the substrate, fine detail had been painted using black, red and green pigments.

Condition

The textile was in a poor condition. The cotton ground fabric, whilst structurally sound, was very soiled and stained throughout. The gilded motifs exhibited extensive cracking; in particular, the foliate motifs in the borders, where the base layer had been applied more thickly, had sustained quite significant losses in places, as the materials had cracked and lost their adhesion to the textile. Remaining elements were flaking and loosely bonded. The overall aesthetic impression was one where there was little definition of design due to the heavy soiling of the substrate, and damage to the border motifs so extensive that some were almost entirely obliterated. The figures and animals in the main field had fared better, and whilst there were losses to the gilding, this was much less extensive.

Analysis

Samples from the motifs were analysed by a historic paint consultant. The silver leaf and the gold leaf were both applied using an oil gilding technique.

The gold leaf was laid over a yellow oil size tinted with finely ground iron oxide yellow.

The silver leaf was laid over a clear oil size. EDX analysis showed that the metal was pure silver, and not an alloy as was sometimes used.  A thin layer of yellowish varnish was applied over the top, presumably to inhibit corrosion and discolouration of the silver.

The pink ground layer was a mixture of a white clay, zinc oxide white, some red and brown iron oxides and a small amount of the pigment chrome yellow [lead chromate].

The presence of the pigments chrome yellow and zinc oxide means the ground must have been applied to this textile in the nineteenth or early twentieth century. Chrome yellow was first introduced as a pigment in 1819, so I fixed that as the earliest this textile could have been made.

Cleaning

The pigments used in the overpainting were highly fugitive (water soluble) if they were touched at all but remained stable if wetted only without mechanical action. I developed a bespoke cleaning method specifically for this textile, using a micro-pressure washer. A jet of water is propelled (with a variable pressure) from a small pencil-like tool, with a range of heads, including a 2mm silicone nozzle, and a small nylon brush. In conjunction with a vacuum suction table and using only cold de-ionised water, I was able to clean around each motif first with the silicon nozzle for accuracy, and then the larger areas in between with the brush. A good level of cleaning was able to be obtained in this way, and as the water was drawn through the textile, I avoided any saturation of the base layer under the gilding.

Using the micro-pressure washer jet

In-filling losses

I used acrylic paints, carefully mixed for colour-matching, to in-fill losses to the gilded motifs where this was significant, and acrylic inks also colour-matched for the decorative over-painting. This restored the overall aesthetic integrity of the piece.

Completion

After treatment, the textile was stitched to an archival quality padded mount, and inserted into a bespoke frame.

Media attention

This project attracted some media attention – see https://www.itv.com/news/central/2020-10-21/conservator-from-hereford-restores-ancient-indian-artwork