The painting's colour scheme follows the lorry's livery. I'd rely on certain pigments to make any colour - put simply: White, 3 Yellows, Orange, 3 Reds, Magenta, Purple, 4 Blues, 2 Greens, Carbon Black, Gold and Silver. Some artists just copy colours they see. Others adapt their own limited set of colours. I use any colour, and go with instinct for what seems right. Sometimes I deliberately leave out one or more of the main ones - Red maybe. For this painting it was a fullish range of Lascaux - with mixes and overlaps to get the muted look. Many moons ago I started off with Abstract art. At 17, after a holiday job as a drivers mate, I dropped out, worked for a few months as a Colour Matcher in a Silk Screen printers, learnt a bit more about colours and saved up enough money for driving lessons to get into lorry driving.