The Swedish film director Roy Andersson describes his collaboration with Walter Hirsch in the book Fotografier 1960-2003 Walter Hirsch, Bokförlaget Arena:

"My first feature film "En kärlekshistoria" (A Swedish love story) was shot in the summer of 1969. At that time it was customary for a still photographer to follow the work on a film set. On someone's recommendation, Europa Film hired Walter Hirsch.
I didn't know him but soon realised that it was a wise choice. It was a commissioned work for the launch of the film. Both the film and the stills were received with enormous enthusiasm. Even today, over forty years later, the film poster with Walter's photo is still in great demand and is constantly being reprinted. In Japan, hundreds of thousands of copies are printed. But Walter Hirsch did not just take photographs to order. It is his free art of photography that is impressive to me.
Describing it is actually not the easiest thing to do. Because it is so open and generous. I would call it inexhaustible."