Matt or gouache colors are those which, after firing, present a dead, dull, opaque surface, entirely devoid of any lustre, and completely concealing the texture and glaze of the ware. The soft, velvet-like quality of these colors is apparent alike to the touch and to the sight.

Matt colors must never be fluxed, unless with the flux made for those particular colors, as one of the attributes of flux is to give additional glaze to colors. The usual flux for ordinary overglaze colors must be kept away from matt colors, to preserve the opaque, flat appearance, which is their distinguishing characteristic.

Some of the best specimens of decoration with matt colors are to be seen among the much admired vases from the Royal Worcester Works. Matt white is used to conceal or deaden the glaze. If color should be applied thin to produce pale tint, without the white, it would be too thin to be matt, and would be semi-glazed.

Matt colors also possess one other property peculiarly their own : viz., gold can be laid over them before firing, but they must first be thoroughly dry and hard. "matt wax" colors are those of a semi-transparent nature, and fill an intermediary place between glazing colors and those devoid of glaze.