Cheap Joe’s Art Stuff offers a variety of artist watercolor painting mediums, such as adhesives, binders and gum arabic to offer the artist the utmost control while watercolor painting. Gum arabic is the binder used in traditional watercolors and gouache. It really is a perfect binder for watercolor because it easily dissolves in water. If you add additional gum arabic to watercolor you can further control the spread of wet color, reduce staining and slow drying time. Dilute with water as required.