Cards throughout the 1960s and 70s, helping them to develop a style manual for their lettering artists. His calligraphy was primarily limited to studies and personal works of art. He also taught calligraphy as a part of his workshops every summer at Rochester Institute of Technology during the 1980s. Computer typography Zapf worked on typography for computer programs from the 1960s onwards. His ideas were considered radical, not taken seriously in Germany, and rejected by the Technische Universität Darmstadt, where he lectured from 1972 to 1981. Because he had no success in Germany, Zapf went to the United States, where he lectured about computerized typesetting, and was invited to speak at Harvard University in 1964. The University of Texas at Austin was also interested in Zapf and offered him a professorship, which he did not take, because his wife opposed a move to that state. Because Zapf's plans for the United States had come to nothing, and because their house in Frankfurt had become too small, Zapf and his wife moved to Darmstadt in 1972. In 1976, Rochester Institute of Technology (RIT) offered Zapf a professorship in typographic computer programming, the first of its kind in the world. He taught there from 1977 to 1987, flying between Darmstadt and Rochester. There he developed his ideas further, with the help of his connections in companies such as IBM and Xerox and his discussions with computer specialists at Rochester. A number of Zapf's students from this time at RIT went on to become influential type designers, including Kris Holmes and Charles Bigelow, who together created the Lucida type family. Other prominent students include the calligrapher and type designer Julian Waters and book designer Jerry Kelly. In 1977, Zapf and his friends Aaron Burns and Herb Lubalin founded Design Processing International, Inc., in New York and developed typographical computer software. It existed until 1986, when Lubalin died. Zapf and Burns founded Zapf, Burns & Company in 1987. Burns, also an expert in typeface design and typography, was in charge of marketing until his death in 1992. Shortly before, two of their employees had stolen Zapf's ideas and founded a company of their own. Zapf knew that he could not run an American company from Darmstadt and did not want to move to New York. Instead, he used his experience to begin the development of a typesetting program, the "Hz-program", building on the hyphenation