1929 | Born in Wandsbek near Hamburg. |
1946-1951 | studies with Alfred Mahlau in the class for free and applied graphics at the Landes-Kunstschule Hamburg, today's HFBK. |
1947 | first autodidactic expressionist attempts in the technique of woodcutting |
1951 | scholarship holder of the German National Academic Foundation |
1952 | Lichtwark scholarship holder; he leaves the Landes-Kunstschule involuntarily |
1952-1960 | Commissioned work (including oil paintings) for the colored paper manufacturer Guido Dessauer in Aschaffenburg. First occupation with lithography. |
1957 | first "Flur" exhibition with large-format color woodcuts |
from 1957 | intensive occupation with the etching technique, guided by Paul Wunderlich |
1964 | art award of the city of Darmstadt |
1965-67 | first exhibition at the Kestner-Gesellschaft, Hanover (the exhibition travels from January 1966 to January 1967 to Hamburg, Darmstadt, Stuttgart, Berlin, Düsseldorf, Lübeck, Basel and Munich); awarded the Edwin-Scharff Prize of the City of Hamburg to Janssen and Paul Wunderlich |
1968 | Participates in the 34th Venice Biennale, Janssen receives the 1st prize for international graphic art there |
1969-1972 | Travels to Scandinavia and Ticino, landscape becomes a new artistic motif for Janssen |
1975 | Schiller Prize of the city of Mannheim |
1978 | Poster exhibition at the Oldenburg City Museum; Biermann-Ratjen Medal of the City of Hamburg |
1980 | Exhibitions at the Art Institute of Chicago and the Busch-Reisinger Museum, Cambridge, USA |
1983-1985 | Touring exhibition in the USA |
1990 | Janssen is awarded the Oldenburg Prize of the Oldenburgische Landschaft (Oldenburg landscape) |
1991 | Exhibition of the "Bobethanien" landscapes in the Albertinum in Dresden; touring exhibition in Japan and Norway; honorary citizenship of the city of Oldenburg |
1995 | died in Hamburg |