Gretl and Leo Wollner met and married in the late 1940s while studying textile design under Eduard Josef Wimmer-Wisgrill, founder of the fashion division of the Wiener Werkstätte; for several years after, Leo worked for architect Josef Hoffmann. Through the 1950s the couple became known for their work with Pausa AG—a German printer known for innovative, high quality designs.
When Barbara Rodes took over the textile division of Knoll International, she initiated a rich collaboration with Pausa and with the Wollners. For Knoll, they developed new printing techniques, including using oversized screens requiring four workers to manipulate, which enabled them to produce floor-to-ceiling prints with no repeat. These were introduced by Knoll as the Three Meter Prints collection: Rivers, Roads, Sails and Trails. Rivers had the additional complication of being printed on velvet with gradations of color mixed as the printing was underway, giving a spontaneous, watercolor effect.