In 1974, Man Ray received the Royal Photographic Society's Progress Medal and Honorary Fellowship "in recognition of any invention, research, publication or other contribution which has resulted in an important advance in the scientific or technological development of photography or imaging in the widest sense." In 1999, ARTnews magazine named Man Ray one of the 25 most influential artists of the 20th century. The publication cited his groundbreaking photography, "his explorations of film, painting, sculpture, collage, assemblage and prototypes of what would eventually be called performance art and conceptual art." ARTnews further stated that "Man Ray offered artists in all media an Example of a creative intelligence that, in its 'pursuit of pleasure and liberty', unlocked every door it came to and walked freely where it would." Seeking pleasure and liberty was one of Ray's guiding principles, along with others such as doing things that are socially prohibited.