Grisaille is a term to describe a monochromatic painting process, used to map out the tone before colour is developed. The Flemish painter Jan van Eyck successfully exploited this technique to develop form and space. Here we will mix two palettes of grey, one with Mars Black for a dark neutral bias and one with Raw Umber for a dark warm grey range, both will be mixed with Underpainting White. Underpainting White is perfect for this purpose as it has a low oil content and is quick drying. Each palette will have 5 colours, bracketed by the darkest colour and white for two of the colours. To begin, a perfect middle tone is mixed; from that middle grey, the darker colour is added to create a darker grey and a fifth mixture is created with the addition of white to the middle grey, to make a lighter grey. These two palettes provide a neutral and a warm range of 5 greys for you to work with. Using these, you can explore underpainting with this limited palette to see how tone creates form.