Winsor & Newton Water Colour Medium, Granulation Medium increases the granulation of color, giving a mottled appearance to colors which usually give a smooth wash (e.g. Winsor Blue), or enhancing the effect of granulating colors (e.g. French Ultramarine). For maximum effect, dilute color generously with medium alone. Always work with painting horizontal. Details:75 ml (2.5 fl. oz.)Increases the granulation of color