Tin-mercury mirror

Description

A reflective surface made from glass backed with a tin-mercury amalgam. Tin-mercury mirrors, also called amalgam mirrors, were produced in Venice as early as 1507 (Hadsund 1993). They were the predominant mirror until the end of the 19th century when they were replaced by silver-backed mirrors. Tin-amalgam mirrors were made by covering a thin sheet of tin with a pool of mercury then sliding a glass plate on top. Pressure is applied to make contact between the glass and tin and push out excess mercury. The mercury-tin crystals are formed surrounded by a rich mercury phase. As the mirror ages, liquid mercury can accumulate at the bottom of the mirror leaving tiny air pockets in some regions. Oxidation of the tin can occur in these locations.

Synonyms and Related Terms

amalgam mirror; espelho estanhado (Port.)

Resources and Citations

• P.Hadsund "The Tin-Mercury Mirror: Its Manufacturing Technique and Deterioration Processes" Studies in Conservation, 38:3-16, 1993.