Watercolour Mediums are used to change the rate of drying, increase gloss, improve flow or blending, add texture or allow layered and juxtaposing washes, often offering a new dimension to paintings.
As they share a similar composition many mediums are also suitable for use with Designers' Gouache including Gum Arabic, Ox Gall Liquid, Aquapasto, Texture Medium, Lifting Preparation and Blending Medium.