Le violon d'Ingres
From The Art and Popular Culture Encyclopedia
Ingres's Violin (French: Le violon d'Ingres) is a 1924 gelatin silver print photograph by Man Ray portraying Alice Prin (aka Kiki de Montparnasse) in the pose of the Valpinçon Bather, a painting by Ingres. Man Ray photographically superimposed sound holes, or f holes, onto the photograph of the back of a female nude, making the woman's body resemble that of a violin.
It was Ingres's well-known passion for playing the violin which gave to the French language a colloquialism, "violon d'Ingres", meaning a second skill beyond the one by which a person is mainly known.