Welcome to Masterclass

Learning tools for artists

Gum Arabic vs Masking Fluid

This masterclass demonstrates the difference between Masking Fluid and Gum Arabic to preserve an area of paper that you want to leave white when using watercolour. Both methods are effective but will give different results. To demonstrate, we paint an area to masked with Masking Fluid and, once dry, paint watercolour on top. Once the colour is also dry, the Masking Fluid can be removed by rubbing and peeling it off to reveal the perfectly preserved white paper underneath. With Gum Arabic, you also paint it over the area you wish to save for white and then you paint over it, but Gum Arabic works by allowing you to wash away colour from the masked area with a wet brush and cloth to reveal white paper again. Masking Fluid leaves a clean, hard edge when it is removed whilst Gum Arabic leaves a softer edge to your white area. When using these materials, it is best to use an older brush since they dry quickly and will leave your brush damaged.

Video Transcript
0:06    Hello, I'd like to show you two ways to mask watercolour using art masking fluid, but also gum arabic. Art masking fluid is an effective medium to mask off areas in your painting. It lets you leave areas of white paper untouched by colour. However, gum arabic can also be used in a similar way, but with a slightly different end result. Brushes should be cleaned immediately after applying either of these fluids and I recommend using an old brush when applying art masking fluid.

0:36    I’m applying some art masking fluid and some gum arabic with a brush to a clean area of watercolour paper. I’ll let both of those dry. Now that both circles are dry, I can apply a colour wash on top, you can see that the art masking fluid looks yellow and repels the wash. While the gum arabic holds the wash in a thin glossy layer. Once that wash is dry, I can remove the art masking fluid by rubbing with my finger, leaving a clean hard edge of masked paper.

1:17    Now for the gum arabic. By using a slightly damp synthetic brush, I can remove the watercolour easily. And this process can be finished by wiping the area lightly with a slightly damp piece of cotton or cloth. The result is a softer masked off area and a technique that's been used by artists like Turner. So here we can clearly see the difference in both masking methods.

I hope you go away and try these techniques for yourself!