What is gum arabic: with artist Rachel Levitas

What is gum arabic: with artist Rachel Levitas

Posted by Cass Art on 11th May 2020

Today I’m going to talk about how to use Gum Arabic in watercolour painting, I also use it in my Oil painting practice but that’s another story! Gum Arabic is a thick, glutinous water-soluble medium that looks a bit like golden treacle. Watercolour paints are essentially pigment, Gum Arabic and a little glycerine, so you if add more Gum Arabic to your mixed paint it will act as an extender; it will make the paint more viscous, so it behaves more like a glaze. The paint sits on the surface of the paper instead of soaking in and takes longer to dry. This is especially useful if you want to create any wash but especially a gradient wash as you have longer to manipulate and blend the paint.

Gum Arabic: an essential piece of studio kit.

What you'll need

Winsor & Newton Gum Arabic

Winsor & Newton Professional Watercolour Tubes

Winsor & Newton Watercolour cold pressed block

Gum Arabic added to mixed paint gives you longer to manipulate and blend the paint.

Because the Gum Arabic has created a soluble layer and has prevented the paint from soaking into the paper it is then easy to lift out soft details from the wash. I’m lifting out these clouds with a damp brush.

Lifting out the clouds with a damp brush or sponge.

A word of warning, the Gum Arabic wash is easily removable so if you intend to tint the entire area with a new colour you may dissolve it; on the other hand, you may like that dissolving effect!

You can also use Gum Arabic as a soft mask, here I’m painting it on with a brush and allowing it to dry completely. When the Gum Arabic is dry, layer your watercolour over it, (this time don’t add any Gum Arabic to your wash, or you’ll lift the lot!)  The Gum will partially dissolve but still retain a soft mask with a different character to the crisp mask of Art Masking Fluid.

Gum Arabic creates a soft , partial mask.

When your wash has dried, carefully lift the Gum Arabic with a damp cloth, I’ve found that staining colours work well with this technique as it is easy to disturb the watercolour while lifting the Gum Arabic.


Shop online for everything you'll need. Don't forget to hashtag #cassart on social media to show us your creations.