Karl Gerstner worked across graphic design, typography and photography. He worked in the art department of Geigy and carried out all the graphic design work connected with the bicentenary celebrations of the firm in 1958. In 1959, Gerstner and copywriter, Markus Kutter, founded the Gerstner+Kutter advertising agency, whose clients included Citroën cars, Krupp, Holzäpfel KG, Schwitter AG, Bech Electronic Centre.