Many French Impressionist artists used cardboard to paint finished works. They used it for its texture and warm brown background color. The cardboard was allowed to show through the layers of paint and was incorporated into the elements of the painting. The oil in oil-based paints is absorbed by an unprimed cardboard support, giving the paint a pleasing, smooth, matte finish. Artists sometimes use pieces of cardboard glued to oil paintings to create papier collé, or paper collage artworks.
Degas often used cardboard to make finished works, as well as Pisarro, Renoir and Monet. The master of this cardboard paintings was without any doubt Toulose- Lautrec followed by Picasso and Vuillard.
Some examples:
http://www.wikipaintings.org/en/claude-m…
The village of Sandviken series were all painted on cardboard:http://www.flickriver.com/photos/7208148…
