In 1971 he was arrested by the StB (the Czechoslovak Secret Police) and imprisoned for "defamation of the allied socialist states". In a graphic cycle created from 1968 to 1971, he included "a distorted portrait of Joseph Stalin, perforated five-pointed red stars or joyful faces of socialist workers turned into a hideous grin".[4] The graphics were identified as "ideologically dangerous" and condemned to destruction. Kulhánek spent a month in prison and was interrogated regularly for next two years.[5] He was prohibited from publishing.
In the 1980s, he created lithographs inspired by the development of the human body. Following the Velvet Revolution, he visited the United States and attended the Lithographic Workshop in Los Angeles. He also often travelled to Belgium, to study the works of old masters.[3]