I usually let them [his drawings] lies around for a long time. I have to get to really like it. And then when I do the painting I have to get to like that too. Sometimes I stay with the sketch, sometimes I follow the original idea exactly if the idea is solved. But most of the time there have to be adjustments during the painting. Through the painting of it I find the color and I work the form and play with it and it adjusts itself.

In an interview by Henry Geldzahler, 'Art International 1.', February 1964, p. 48