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 paper. When all moisture evaporates, the acacia gum typically does not bind the pigment to the paper surface, but is totally absorbed by deeper layers. If little water is used, after evaporation the acacia gum functions as a true binder in a paint film, increasing luminosity and helping prevent the colors from lightening. Gum arabic allows more subtle control over washes, because it facilitates the dispersion of the pigment particles. In addition, acacia gum slows evaporation of water, giving slightly longer working time. The addition of a little gum arabic to watercolor pigment and water allows for easier lifting of