Composition and effects of different types of varnish, with its visual effects, and how it can make a painting unreadable when it contains accumulated dirt.
varnish
Defines and explains key terms, from the support, through the ground and paint layer with its binder and diluent, to the varnish to protect its surface.
Varnish has been applied to protect the paint layer. But layers of old varnish discolour and trap dirt and contaminants, letting a painting vanish into the dark.
Until 1880, varnishing oil paintings was standard practice, but three completely different types of varnish were used. A journey through names like sandarac and colophony.
The Eclectic Light Company 