Gilding
Chalk & Glue
Chalk is a naturally occurring rock, which was formed by the deposition of smallest marine organisms about 70 million years ago.
Glue is obtained from animal tissue, especially skin and bones. These can be filtered by boiling.
The carrier of these substances is the protein collagen, which transforms into water-soluble protein glue by heat exposure. The glutin causes the sticking and binding power of the glue. This process is the case in all glues produced from animal tissue, therfore skin, bone and fish glues are also called gluten glue.
Chalk
Stone Chalk – Pulverised soft limestone from alpine rock forms.
Champagne Chalk – This name means a precise denomination of origin, because this chalk comes from the area around Reims (Champagne region).
Bologna Chalk – The name chalk is not entirely correct for this material, because it is a calcium sulfate (gypsum).
China-Clay – This is not a true chalk, but siliceous alumina (aluminum silicate), a weathering product of feldspar rocks.
Glue
Bone Glue in grains
Rabbit Skin Glue in grains
Skin Glue in grains