Gum arabic is added to watercolors to increase brilliancy, gloss and transparency. You can also use it for controlling spread when painting wet-on-wet.
In my painting Beyond Nature (watercolor on paper, 21 ? x 29 at right), I wanted to recreate the light of the sun going down at twilight. In order to do this, I decided that I had to make the trees very dark to create the contrast I needed, so I added a small amount of gum arabic to a mixture of sap green and sepia to get my greens darker.
A hint for trying this yourself: Start by adding only a small amount of gum arabic. Too much can make the paint shiny and muddy. Practice with it first before you apply it to your painting.
Loraine Crouch is assistant editor for The Artist’s Magazine.