Since the 1950s most mirror makers have an aluminum coating applied by a thin-film deposition process (work is done by a firm specializing in the process). Modern coatings usually consist of an aluminum layer overcoated with protective transparent compounds.
Since the 1950s most mirror makers have an aluminum coating applied by a thin-film deposition process (work is done by a firm specializing in the process) Modern coatings usually consist of an aluminum layer overcoated with protective transparent compounds.