Dead of night
Bitumen paint is made to repair a leaking roof. It is dreadful stuff to work with, sticky, stinking and as black as can be. It is like the dregs of a barrel of crude oil, but when dried on a painting it can be a sublime, rich, and deep black. Pure black like Japanese lacquer, but with a velvety softness. This contrasts with a thin transparent wash of blue through which light shines and bounces back off the white base so illuminating the colour from behind. A strip of cast silver coloured metal (mostly tin) is embedded in the paint.