Quick Overview
Colophony is a by-product of the distillation of turpentine. It is soluble in most solvents, but considered an adulterant in varnishes and paints, as it forms a weak surface that is prone to darkening and cracking. It is, however, a key ingredient in wax-based etching grounds, imparting hardness, and can be used in powdered form (rosin) to make aquatints.