In 1959, Rowntree became Professor of Fine Art at Durham University and it was there that he came into contact with Victor Pasmore, precipitating a further 90° turn in his work. During the 1960s and 1970s, he created a series of bright, hard-edged, geometric, non-figurative works, often incorporating lettering, either painted or collaged. He also delighted in recycling and reworking objets trouvés and bits of old packing cases, complete with stencilled names and addresses.