Hein Gravenhorst is a German artist and photographer known for generative photography.

Decisive for my path toward photographic art, however, was the exhibition Generative Photography, which I myself conceived and installed in 1968 at the Kunsthaus Bielefeld. It became a signal for concrete-constructive, serial photographic work and brought together my pinhole-aperture structures with Cordier’s chemigrams, Kilian Breier’s luminograms and Hein Gravenhorst’s photomechanical transformations.
Gottfried Jäger, Gottfried Jäger on a New Kind of Being
No question that Victor Vasarely's manifesto was a super important moment in art history, and also there is a strong relevance of kinetic and op art for the artists who later, I mean, like I mentioned Hein Gravenhorst, for example, who did op art as a generative photographer.
Georg Bak, Georg Bak on the Analog Era: 1950s Art