Complex sentence: Kulmer worked in the studio of Krsto Hegedušić from 1950 to 1957, and was appointed an assistant to Hegedušić at the Academy of Fine Arts in 1961, becoming a full professor there in 1969.
Split into simpler sentences: Kulmer worked in the studio of Krsto Hegedušić from 1950 to 1957. He was appointed an assistant to Hegedušić at the Academy of Fine Arts in 1961, becoming a full professor there in 1969.