What a wonderful natural product. The white of an egg. First mentioned as early as the 5th century. Used extensively in the 13th & 14th century throughout the middle east and Europe as an adhesive to dilute Gesso and other sizes in the application process of applying Gold to vellum. Glair would make the size flow easier and allow its tack to be strong. Gold was heavier in weight, so Glair was an external size that made the attachment of metal easier on vellum. 

Cennini in the 14th century NEVER used water to dilute the Gesso or any of the other sizes being used. Just a few drops of Glair made the application process easier . A natural adhesive born from decomposing

Cennini took the white of the eggs, processed it and buried it for a minimum of 6 months in the ground. It putrefied. Commonly called "La Prutredo" because of its smell as it continued breaking down . The odor: rotten eggs

Glair when first made is used as a varnish Once the decaying process begins, as Glair ages it becomes an adhesive. the older it gets the stronger the adhesive 

As the Glair decomposes, it should be strained once every 2 to 3 months to eliminate any  stringiness debris that may be present.  Once the aging process is complete, no further straining is necessary.

We have added a very small amount of a mold inhibitor to prevent mold. Has no effect on the Glair either in room temperature or even if the Glair was refrigerated.  

Use it sparingly. One or two drops on the adhesive you want to reduce to make the size more MANAGABLE. The tool also plays an important role in the size application. 

One final note; make sure that the tool being used in the application process is dipped in water and cleaned. Egg is difficult to remove once dry.   

          JERRY TRESSER  [email protected]