Casein – Casein is a phosphoprotein found in milk that can be dried down to a very fine powder substance. Since ancient times, casein has been used as an adhesive for wooden objects and as a binder for water-born paints. Common recipes for preparing casein as a binding medium involve the addition of ammonia carbonate or borax.
Fish Glue – Gelatin is obtained from the bones of fish and can come in sheet or powdered form. Its adhesive properties have been known for hundreds of years although gelatin tends to be more refined then other glues as it is frequently used in the preparation of food. Isinglass differs from gelatin in that it is collected by soaking the bladders of the Russian Sturgeon fish and considered to be a fish glue of the highest quality due to its strength. While both have been used as adhesives and consolidants for paper and painted objects,
Funori – Funori is a polysaccharide-based adhesive that is collected from at least three types of red seaweed found along the coastlines of Japan. It has been used for hundreds of years as an adhesive for mounting Japanese silk paintings and is still used today for mending and repairing paper objects.
Hide Glue – Hide glue is a generic term for collagen obtained from a range of domesticated animals. Historically hide glue was often prepared from scraps of parchment or discarded bits of leather. As with rabbit-skin glue, hide glue has been used since ancient times as an adhesive and sizing material.
Rabbit Skin – This collagen-based glue can be purchased in sheet form, as pellets, or a fine powder. Many commercially available forms of rabbit-skin glue may have additions of collagen obtained from the hides of cows, sheep, goats, or horses. Used both as an adhesive and as a sizing material for easel paintings, it became popular during the early Renaissance. Rabbit-skin glue has also been used as a mordant, an additive to gesso and as a binding medium (distemper paints).Wheat Starch Paste (not pictured) – Used by the Romans and Egyptians, pure extracted starch paste is known for its excellent adhesive properties. Although starch paste can be obtained from a variety of flours, today wheat flour is primarily considered to produce starch paste of the highest quality for mending paper objects.