Cameo Glass - Techniques

Techniques

In the modern revival all of the top layer except the areas needed for the design are usually removed by an etching process — the figure areas are covered with a resist layer of wax or some other acid-resistant material such as bituminous paint, and the blank repeatedly dipped in hydrofluoric acid, so that cameo glass is in some sense a sub-set of acid-etched glass. The detailed work is then done with wheels and drills, before finishing, and usually polishing. It seems that in the ancient world the entire process of removing the unwanted white or other top layer was done by drills and wheels — wheel-cut decoration on glass of a single color was very common in ancient Rome. In the case of "three-layer" (or three-color) cameo, there is another layer of glass on top of the white opaque one, and further layers are possible. One Roman piece uses a record six layers. It is not known where the Roman pieces were produced, but for want of any better suggestion most scholars think in the capital itself. It appears likely that at least the making of the blanks was initially in the hands of imported Syrian glass-workers.