In the optical industry, there are three main families of materials used to make frames: organic or plastic materials, “natural” materials, and metals.
Composites (carbon, Kevlar, epoxy resin) are not widely used due to their particular implementation and the difficulty of obtaining small aesthetic parts.
There are different types of surface treatments. However, two large families are distinguished: galvanic and organic treatments.
Solutions containing noble metals (such as gold, palladium) or more common ones (such as chrome, ruthenium, bronze, nickel) lead to an electrolytic deposition of a thin layer of these metals on the metal frame.
Paints, epoxy or polyurethane varnishes, transparent or opaque, colorless or tinted, require baking after being deposited by spray onto the metal or plastic frame
Less commonly, other techniques can be used: