The power of layering works wonderfully and is a fantastic effect for the rich, vivacious paint that is gouache. You can use white oil paint, as this helps to repel any gouache paint and the area will remain white. Gouache Painting Step By Step - Clare Willcocks Art Gouache Painting Gouche Painting Gouache Art Start with small sketches in gouache and focus on painting light filled paintings. What to paint on with gouache . It is the contrast between light and dark shapes and warm and cool color that brings the best out of this medium. Gouache is a type of paint which is centuries old, and yet relatively few people even know of its existence today. Gouache can be painted on colored papers since it's more opaque than watercolors. Opaque layers are used to disguise hidden layers underneath. Blooms can be used to add in a base of colour you can then paint on top of. To achieve the look and feel of watercolor, just add more water to your gouache. I load my brush wi...