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 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 which a specially treated platinum print photograph is coated with washes of gum arabic, then re-exposed to the same photographic negative. The finished process results in a sepia toned print, and is said to impart added luminosity and depth. It is sometimes called "pigment over platinum". To sensitize the gum arabic it must first be placed in contact with ammonium or potassium dichromate. Gum arabic is not photosensitive by itself. To clear the chromic