Gum arabic
Gum arabic is used as a binder for watercolor painting because it dissolves easily in water. Pigment of any colour is suspended in the acacia gum to get in watercolor paint. Water acts as a vehicle to thin the watercolor paint and helps to transfer the paint to a surface such as paper. When all moisture evaporates, the acacia gum binds the pigment to the paper surface. After the water evaporates, the acacia gum in the paint film increases luminosity and helps prevent the colors from lightening. Gum arabic allows more precise control over washes, because it prevents them from flowing or bleeding beyond the brush stroke. In addition, acacia gum slows evaporation of water, giving slightly longer working time.