Glass engraving in the context of "Roman glass"

Engraving is the practice of incising a design on a hard, usually flat surface by cutting grooves into it with a burin. The result may be a decorated object in itself, as when silver, gold, steel, or glass are engraved, or may provide an intaglio printing plate, of copper or another metal, for printing images on paper as prints or illustrations; these images are also called "engravings". Engraving is one of the oldest and most important techniques in printmaking. Wood engravings, a form of relief printing and stone engravings, such as petroglyphs, are not covered in this article.

Engraving was a historically important method of producing images on paper in artistic printmaking, in mapmaking, and also for commercial reproductions and illustrations for books and magazines. It has long been replaced by various photographic processes in its commercial applications and, partly because of the difficulty of learning the technique, is much less common in printmaking, where it has been largely replaced by etching and other techniques.

Enamelled glass or painted glass is glass which has been decorated with vitreous enamel (powdered glass, usually mixed with a binder) and then fired to fuse the glasses. It can produce brilliant and long-lasting colours, and be translucent or opaque. Unlike most methods of decorating glass, it allows painting using several colours, and along with glass engraving, has historically been the main technique used to create the full range of image types on glass.

All proper uses of the term "enamel" refer to glass made into some flexible form, put into place on an object in another material, and then melted by heat to fuse them with the object. It is called vitreous enamel or just "enamel" when used on metal surfaces, and "enamelled" overglaze decoration when on pottery, especially on porcelain. Here the supporting surface is glass. All three versions of the technique have been used to make brush-painted images, which on glass and pottery are the normal use of the technique.

Cameo glass is a luxury form of glass art produced by cameo glass engraving or etching and carving through fused layers of differently colored glass to produce designs, usually with white opaque glass figures and motifs on a dark-colored background. The technique is first seen in ancient Roman art of about 30 BC, where it was an alternative to the more luxurious 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.

From the mid-19th century there was a revival of cameo glass, suited equally to Neo-Grec taste and the French Art Nouveau practiced by Émile Gallé. Cameo glass is still produced today.