Abstract
Baking conditions for the preparation of gold-layer photographs via transcription on a porcelain base were investigated with the aim of increasing the durability of the photographs. It was found that increasing the maximum baking temperature increased the durability of the gold layer against scratching. This increase, however, brought about a reddening of the image and a decrease in the maximum optical reflection density. Images from the photographs that were baked above 900°C were retained even after scratching the photograph with sandpaper or dissolution of the gold layer in a tincture of iodine. It is proposed that the glaze layer on the porcelain base softened up after baking at temperatures above 800–900°C and that the gold layer gradually sank into the glaze layer. At the same time, the boundary between the gold and glaze layers fused, increasing the adherence of the gold layer to the glaze layer.
https://ror.org/01hjzeq58 
