Two square paintings about colour itself, and nothing else.

Materia is the quietest corner of Wildcabinet – colourful abstract watercolour, where the medium is the subject and there is nothing to picture. Only pigment, and what it does when you let it move.

Prima Materia came first – the first painting I ever gave real, sustained time to. "First matter" is the alchemists' word for the substance everything is made from, and that is what this turned out to be – the matter all my other work grew from. It is built one dot at a time. A bead of water, pigment let to bleed into it, some drawn back with the corner of a tissue, gold where it wants gold, thousands of times by hand. I control the edges. What happens inside, I can't, and that is the whole point. There is always one going somewhere in the studio, in different colours.

Flow is its twin and its opposite. Where Prima Materia asks for your focus, Flow asks nothing at all – my whole palette let loose and falling together, with no puzzle in it and no answer wanted. The one painting here made purely to sit quietly in front of. The dot born in Prima Materia still surfaces all through the other paintings. Between them they are the practice at its poles – the focus everything grew from, and the calm to set beside it.

Nothing and everything. Just colour, doing what watercolour does when you stop telling it what to be.