glair

Glair is a historical term rooted in the white of eggs (albumen). The word comes from Old French glaire and has two main senses in recorded usage. In culinary and everyday contexts, glair describes the white of eggs itself or its prepared forms. In the history of art, glair refers to a binding medium made from egg whites and used by medieval and early Renaissance painters as a tempera binder and as an adhesive for gilding and sizing.

Preparation typically involved beating fresh egg whites with water until slightly foamy, then applying the mixture to a surface where it dried to a transparent film. When used with pigments, glair created a fast-drying, relatively durable paint medium that preceded the adoption of more modern binders. Glair is sensitive to heat and humidity and tends to deteriorate over time, often yellowing and becoming brittle.

In modern times, glair is primarily of historical interest. It is discussed in art-conservation literature and in discussions of archaic painting techniques. The term also appears in dictionaries and culinary references as a historical name for egg white.