This natural insect secretion is the basic component for any “classic” protective finish. In alcoholic solution, it is applied with various techniques directly on the applied metal leaf and preserves it from possible, subsequent oxidations; you can use Shellac on top of the gesso before applying the gilding size to prevent the size from mixing with gesso.
To dissolve: for every 100g of Shellac add 1 litre of alcohol.
The light transparent layer is particularly resistant to scratches and gives a final protection to the product. Shellac is a resinous substance that is secreted by an insect – the enamel shield louse. It accumulates on the branches of trees. Found mainly in south and south east Asia, particularly in India and Thailand, shellac was manufactured formerly in large quantities. The annual output amounted to about 50,000 tons. In order to harvest a kilogram of shellac, one needs about 300,000 enamel shield lice. For the gilder, shellac is mainly used as a protective coating. The use of shellac is restricted to the painting technique. Shellac is only usable for inside.