Clouds are effected by light and perspective in the same way as any other large three dimensional object. They will be illuminated on the surfaces struck by the sun, and in varying degrees of shadow elsewhere. The underside of a cloud usually has the darkest shadow.

A large cloud will cast a large shadow on the ground. Because of the effect of perspective, cloud shadows on the ground appear as a dark band through the landscape. Exaggerating the tonal contrast caused by cloud shadows can add greatly to the drama in a painting

Alizarin, Ultramarine, Prussian and a small amount of Raw Sienna can also be used to paint clouds.