When I was young I was more obsessed with the materiality of things.... today I am more interested in air and atmosphere. This is why I deliberately treat space ambivalently. For example, an orange painting with white lines might be viewed as an orange wall with white lines, but the orange colour is no less atmospheric for all of that. It abounds white light, and the white line vibrate in a deep space, too, as well as an orange 'wall'.

In an interview with Irmeline Lebeer, in 'Recent Work', Princeton Art Museum, 1973 pp. 10-13 - after 1970