Albumin

Known and used since ancient Roman times, it is a glue made from egg white. Used as a protein binder for tempera and watercolor painting. Traditionally, albumin has been used, mixed with white sugar, also to paint paintings in a non-permanent way, the sugar, in fact, prevents the egg white from becoming insoluble. In the event that the albumin has been applied pure, it cannot be dissolved by water, alcohol or even oils, it makes the painted surface waterproof.