Gouache the formula of the paint is "acrylic gouache". Its highly concentrated pigment is similar to traditional gouache, but it is mixed with an acrylic-based binder, unlike traditional gouache, which is tempered with gum arabic. It is water-soluble when wet and dries to a matte, opaque and water-resistant surface when dry. Acrylic gouache differs from acrylic paint because it contains additives to ensure the matte finish and the reworking time is slightly extended. Some brands can sometimes be removed or "lifted" for several hours after application, during their drying time. Gouache Gouache (; ), body color, opaque watercolor, or gouache, is
Gum over platinum acid, the print is washed in 1% potassium metabisulfite after proper development in water. Interested individuals should read up on the process before attempting, as the chromic acids are very dangerous to work with. The mechanics of the gum portion is not entirely known; what occurs is the exposed gum is hardened and becomes water-insoluble. Upon washing, the unexposed portions wash away, leaving the white paper exposed. The technique is related to platinum printing. Gum over platinum Gum over platinum is a historical chemical photographic process, which was commonly used in art photography. It is a very complex process, in