This technique was perfected by the early painters, using oils. They would lay thin skins of transparent pigment one over the other to create colours of incredible richness and luminosity (cf Rembrandt & Rubens). The technique was further developed in to watercolour by Cotman. Acrylic paint is well suited to the glazing technique because it dries so fast. Each applied layer must be thoroughly dry before the application of the next one. The effect is different from impasto, opaque painting as the light appears to reflect through each layer, almost giving the appearance of lighting from within. Special media can be purchased for acrylic glazing, both in gloss and matt. David Hockney is renowned for his acrylic paintings, which are based on glazes.