Paper in its different forms has been the preferred support for many artists, for writing, drawing or painting. Its composition varied with time and geographical origin. Made of rags at the beginning, the industrial production from the 19th century onwards used chemically treated wood fibres as a raw material, with resins, minerals, glue and other added ingredients. Some papers carry watermarks indicating their origin.
The scientific investigation of a work of art on paper always involves inspection in ultraviolet light. Why? From the 1940’s onwards optical brighteners were often added to mass produced paper. This observation can be an indication of the real age of an artwork. Radiocarbon dating is another option for a more precise dating of an artwork.