Tony Cairo [English abstract sculptor] and I tried to collaborate at several points and it hasn't been successful. As a matter of fact, recently Tony has made sculpture that I have painted. He has to make the sculpture before I can paint it. That means that the form is taking precedence – that the material takes precedence as a form, rather than color establishing the form. It's not going to well but I'm working on it. There's something about color that is so abstract that it is difficult for it to function in conjunction with solid form... Color has properties of weight, density, transparency, and so forth. And when it also has to be compatible with things that have an actual density, a given form, it's very difficult.

pp. 99 – 105 - 'Color, Format and Abstract Art' (May – June 1977)