The use of Gum Arabic was puzzling to understand when I began watercolor painting a long time ago since I thought it was only used in foods. There are two forms of Gum Arabic that I have found available for artists to use in watercolors. These forms of Gum Arabic are liquid and dried. Similar to Chinese or Japanese inks, you can purchase dried Gum Arabic in small packages that look similar to manila mailing envelopes. The liquid form is more readily available since it is ready to use with watercolor paints.
Uses of Gum Arabic in Watercolor paintings are not all that varied, at least what I have discovered. The first and most common use is to add body – thicken – to watercolor paint without losing the value of the color. Use the Gum Arabic sparingly because too much added to the paints will cause it to chip later on. It is one of those Catch 22 mediums that will either make or break the painting. Adding Gum Arabic to watercolor also gives it a more glossy appearance to the overall painting.
Since Gum Arabic is basically a binding compound for watercolors, it can also be diluted to become the basic clear wash to be laid on the paper, board or canvas. Whether it dries up too fast or not will not matter, as it will allow the watercolor paints to adhere better to the surface being painted upon. The overlaying of colors for a transparent look in the painting works well when the first layer of paint is completely dried followed with Gum Arabic mixed with the next color. Remember not to use too much Gum Arabic, but just enough to make the painting look the way you want it to appear.
The only other use I have found for Gum Arabic is to make your own watercolor, gouache and pastels. Since it is a binder, all you need are the primary pigmentations and a little filler of some sort to create one of the three medias. More than likely the filler is what determines which of these three the Gum Arabic and pigment will form. There are many recipes on the internet showing you how to make your own watercolor paints. Dextrin just happens to be the most common filler among manufacturers of watercolor paints.
As mentioned earlier, great care should be taken in the use of Gum Arabic. It can be rewetted just as watercolor paints in case it dries up. Storing the dried compound in a cool dark place is best for Gum Arabic. Granted, you will find it in lit areas in stores, but think of it this way. If paints can yellow being exposed to light, why would the compounds that make them not yellow if exposed to light as well? Maybe I am being too cautious with my own paintings, but wouldn’t you?
Most art stores sell Gum Arabic in liquid form, and they may also have a free pamphlet for watercolor paints to re-inform you how to use them. The other pluses to using Gum Arabic are that it creates a better transparency appeal and it slows down drying time. It also gives greater depth and is more luminous than regular color washes. The fun with painting with watercolor is that it is an ongoing learning process especially with a medium such as Gum Arabic.
