|Kelsey Murphy with some of her Cameo Glass|
Cameo glass is a luxury form of glass art usually with white opaque glass figures and motifs on a dark-colored background. The technique is first seen in ancient Roman art of about 30BC, where it was an alternative to the luxury engraved gem vessels in cameo style that used naturally layered semi-precious gemstones such as onyx and agate. Glass allowed consistent and predictable colored layers, even for round objects.
|Émile Gallé Cameo Vase|
Judging from the very limited number of survivals, cameo glass was apparently produced in two periods: the early period about 30BC to 60AD, and then for about a century from the late 3rd century to the period of Constantine the Great and his sons. The latter period also saw a brief revival of the art of gem-carving, which had been in decline.
Glass from the later period is even rarer than from the earlier, with only a "handful" of complete pieces known, one of which was excavated in Norway. Its use was clearly restricted to the elite. The Portland Vase is said to have been excavated from the tomb of the Emperor Septimus Severus, for whom it would have been a 200 year-old antique. The most popular color scheme for objects from the early period is white over blue, as in the vase from Pompeii, but other colors are found, such as the white over black Portland Vase. In the early period usually all layers are opaque. By contrast, in the later period, there is a translucent colored overlay over a virtually colorless background. The surface of the top layer elements is flat rather than carved as in the earlier group of pieces.
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. One Roman piece uses 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. It is almost impossible to do 6 layers today so how the Syrians did it is still a mystery.
The French makers were not content to make the same type of vases again and again, so they experimented with various techniques to achieve different results. It is thought that the technique of mold-blowing by the firm of Emile Gallé was not added to their repertoire until after WWI. By that time, Emile Gallé had already died.
In the United States, Kelsey Murphy uses a gathered glass rather than the mold blown so the layers of glass are much thicker giving a fantastically high relief.
Blown-out vases can be of identical form, but not identical. They will differ in color, depending on the choice of colored glass used to cover the blank. They may also differ slightly in design, depending on the etching.
Gallé produced approximately fifty different models of blown-out vases, from small to huge.
Other companies, such as Daum, employed the technique of mold-blowing, but Gallé embraced the technique and produced the largest number of different blown-out vases.