Ox gall is an extremely useful medium for watercolour artists. It increases the wetting properties and flow of watercolours with a few drops to your painting water. The medium also allows colours to soften and blend together easier. This medium gives shine and brightness to watercolours and does not affect the surface colour tone.

Ox gall can also improve the acceptance of watercolour on paper - particularly hard-sized papers. It will also set your colours into the paper and make them harder to lift. As a result, this medium can be useful for ‘marbling’ or creating textures. If you want to create paintings with several colour layers, ox gall is the way to go.