Gouache to acrylic or oil paints in that it is normally used in an opaque painting style and it can form a superficial layer. Many manufacturers of watercolor paints also produce gouache and the two can easily be used together. Gouache paint is similar to watercolor, however modified to make it opaque. Just as in watercolor, the binding agent has traditionally been gum arabic but since the late nineteenth century cheaper varieties use yellow dextrin. When the paint is sold as a paste, e.g. in tubes, the dextrin has usually been mixed with an equal volume of water. To improve the
Gum arabic that "based on present scientific knowledge only an arbitrary value can be used for regulatory purposes". In 2008 the FDA sent a letter of no objection in response to an application to reduce the rated caloric value of gum arabic to 1.7 kcal/g. Gum arabic is used as a binder for watercolor painting because it dissolves easily in water. Pigment of any color is suspended within the acacia gum in varying amounts, resulting in watercolor paint. Water acts as a vehicle or a diluent to thin the watercolor paint and helps to transfer the paint to a surface such as