First used in Roman and Egyptian antiquity, enamelling on glass and crystal made Art Nouveau glassware famous at the end of the 19th century. This decoration technique consists in painting a pattern on a glass support with enamels. These very fine vitrifiable powders, coloured by oxides, cook and melt at low temperatures, thanks to the presence of a fusible base. The paste is made by mixing the glass powders with an oily substance such as Arabic gum. The piece is then annealed in a kiln at a temperature of 1,110°F (600°C) to fix the decoration.