EAC

A discolored and water-stained etching before and after treatment.

Pith "paper" is not paper, even though it is often called "rice paper"; it is a misnomer. Pith behaves differently than paper because it has a different structure. It is more fragile than the thinnest paper, and can be easily crushed and damaged. Traditionally pith sheets were produced in China to be used for painting and decorations (manufacture of artificial flowers for example). Chinese pith paintings became all the rage in 19th c. and were often sold to the visiting westerners. An example of a pith painting and an magnified detail of the white background is shown in the photographs below.