Conserving a silk hanging scroll painting: Portrait of Minamoto no Yoritomo
The texture and appearance of silk is affected by the density and type of weave. Early Japanese paintings tended to be painted on silk with a fairly open weave. There are many different types of silk so it is very important in the conservation of a silk painting to match the weave of the repair silk as accurately as possible to that of the original. The repair silk used in the conservation of this painting was woven to order. It was then exposed to a radio-active source: a recognized method of weakening newly woven silk so that the qualities of the new silk will be sympathetic to those of the original painting.
Each area of loss had to be carefully traced and a repair cut to exactly the same size before being placed into position on the painting. The silk repairs were attached using a mixture of Japanese gluten-free wheat starch paste and funori, an adhesive prepared from seaweed. This adhesive is used as it is not only readily reversible but also extremely flexible. Prior to any retouching the new repair is sized with a dilute soya milk solution. This enables the retouching to remain on the surface of the repair without spreading into the surrounding painting.