A detail of a finished patch of sand. Over the dark spatters I then sprayed on a lighter colour using the same technique. In theory some of these lighter spatters will overlay parts of the darker ones giving the impression of grains of sand. Had I wanted to create a pitted surface I would have put the light colour on first and overlaid with the dark, giving the appearance of tiny dimples where the dark spots partly obscure the lighter ones. I have then added a few larger 'grains' by dabbing the paint on with the tip of a painting knife, again putting dark spots on first and slightly offsetting lighter spots on top of these but just to their right, thus giving the appearance of cast shadows.