Stefan Knapp is best known for his vibrant enamel murals which can be seen in many museums and public buildings throughout the world. He was the first artist to experiment with enamel on steel on a large scale. In 1939, when he was eighteen, Knapp was imprisoned and sent to a labour camp in Siberia. This imprisonment, as well as his experience as a RAF Spitfire pilot between 1942-45, was to have a profound effect on his artistic development - he used painting as a way to exercise his mind.
He became more involved in the process of adapting and perfecting enamelling methods for steel instead of the traditional copper, and found that his style of painting was changing and becoming more abstract and his colours brighter. Between 1954 and 1968 he showed at least once a year, with nineteen one man shows in galleries and five in international museums.