Gouache
An opaque, matt water-based paint, like watercolour with more pigment and added white.
Also: opaque watercolour, body colour, poster colour
Gouache uses the same gum binder as watercolour but is made to cover. It contains more pigment, and often chalk or white, so a light colour can be painted over a dark one. It dries to a flat, velvety surface that photographs well, which made it the standard paint of illustrators and poster designers in the 20th century. Indian and Persian miniature paintings were made in a similar opaque watercolour. The colours shift slightly as they dry: lights dry darker and darks dry lighter.