This paper presents a method of colouring pictures by using three kinds of gradation techniques: gradation from a figure to a point, gradation from a figure to a line segment and gradation from a figure to another figure. Intermediate figures are computed by homothesis or interpolation. The gradation is obtained by colouring these intermediate figures. The colours are simulated by using programmed pattern. This approach has allowed us to produce realistic images with a hardware device that is not very good for these types of applications. because of its restricted intensity and colour capabilities. Colour distribution algorithms and gradation techniques are explained in detail. A few examples with shading and texture are shown.