Grisaille is not a paintings type by its own but an initial step in  . It is the step representing lighter shades of the image to be painted. This type grisaille grey is basically a painting in lighter grey shade (followed as per the rules of oil painting the darker painting section follows the lighter colors to be implemented in oil painting) before the   is all done. This painting is executed entirely on monochrome in various shades of grey which can also be used for decorative purposes such as representing an object in relief.