Gouache is an opaque, water-soluble paint that differs from watercolour, meaning it stops the white paper surface showing through.
Gouache is essentially watercolour paint with added white pigment, giving it an opaque quality. This opaque nature means it dries to a flat, matte finish and reproduces exceptionally well, making it particularly suitable for commercial art, illustration, and posters. White gouache is also commonly used to add strong highlights to watercolour paintings.
Designer's or artist's gouache uses high-quality pigments to achieve vibrant, lightfast colours that are smooth and solid. It dries quickly, delivers bold results, and doesn't require any additional mediums. It's popular among students and commercial artists and is often a required material in art colleges. Gouache can be used directly from the tube or thinned with water for washes, but it doesn't allow for building up multiple layers like pure watercolour. Unlike acrylic, gouache isn’t waterproof when dry.