During the seventeenth and eighteenth centuries, the use of enamels became widespread, replacing the old methods of coloring glass - pot metal, flashing, and staining. Colored enamels seldom have the brilliance of pot-metal glass but can take on a rich translucence when carefully applied. Enamels are compounds of ground glass and oxides that become fairly transparent when heated and fused to clear or white glass.

Enamels are soft powdered coloured glass that are mixed with a medium and painted onto the glass with a brush.  Deposits of special mineral pigments on the glass surface which vitrify at the annealing or tempering temperatures are stable, non-biodegradable deposits, and can be produced in one or more colours, and in different figures (tips, letters, and pads). When the medium is dry, the glass is placed in a kiln for firing.

Enamelled glass is tempered or heat-strengthened glass, one face of which is covered, either partially or totally, with mineral pigments. In addition to its decorative function, enamelled glass is also a solar ray controller.

Manufacturing Process

Glass is covered by some metallic oxide, and rendered opaque by the presence of arsenic trioxide, or an equally fusible transparent glass, mixed with some opaque infusible powder. It is always applied as a pigment, and is fixed to the glass background by heat. It is essentially a glass, and by heat should become partially incorporated with the glass upon which it is painted.

Applications

Enamelled glass can be used both internally and externally. Externally it can be used for overhead glazing such as in canopies. Internally it can be used for wall cladding and furniture and is particularly useful where resistance to humidity is required. Enamelled glass is used for glazing and for cladding in facades and roofs. Enamelled glass is also used in insulated spandrels or cladding panels in non-vision areas for an aesthetically clean appearance. It can be assembled into laminated glass or glazed insulation.