Black 

Large solid areas of black will draw too much attention. Tones will give form, but if it is so dark that  there is no change in tone, then change the temperature – warmer or cooler. Black can be mixed, but you need to use pure darks without any white in them e.g. swing to a  warmer dark with alizarin crimson. Other useful darks include intense blue, Prussian blue,  viridian, French ultramarine. Any white will make the mix muddy. 

Pure Colour 

Blocks of pure colour added emphasis to the painting.