Painter, printer and illustrator Ruth Collet (née Salaman) was born into an Anglo-Jewish family of Ashkenazi descent (who had migrated to Britain from either Holland or the Rhineland in the early 18th century) in Barley, Hertfordshire, England in 1909. Her father was the botanist Redcliffe N. Salaman (1874-1955), and her mother was the Hebrew scholar Nina Ruth Davis (1877-1925). Following her mother's death, her father married Gertrude Solomon, niece of the painter Lily Delissa Joseph. Among Ruth Collet's cousins were the artists Michael Jonathan Salaman and Merula Salaman (later Guinness).

As Ruth Salaman, she studied drawing and painting at the Slade School of Fine Art under Henry Tonks and Philip Wilson Steer (1927-30). Before her marriage to musician Robert Collet, Salaman was much associated with the East London Group, afterwards they lived for several years in Paris, where she studied etching at Atelier 17 under Stanley William Hayter (1932-35), completing her studies, after her return to London, at the private art school of New Zealand-born Kathleen Browne and her Polish émigré husband Marian Kratochwil. Collet was a proflic artist working in a range of media including oils, watercolours, gouache, woodcuts and etching. She exhibited widely with the Royal Academy (from 1938), the Artists International Association (AIA), including in the For Liberty exhibition in 1943; with the New English Art Club (NEAC, from 1944), the London Group, the Royal Society of British Artists, the Society of Women Artists, and the Women's International Art Club (1952–76), including on the executive and selection committee in 1958. She had a one-room solo exhibition at the Goupil Gallery, London in 1938 and three major exhibitions at Ben Uri Gallery: with Adele Reifenberg and Julius Rosenbaum in 1950; with Lottie Reizenstein and Frances Baruch in 1970; and with Margaret Levinson in 1978. She also held solo London exhibitions at the Annexe Gallery (1982), the Sue Rankin Gallery (1987), the Sternberg Centre for Judaism (1991) and the Moss Gallery (1991). Her work was influenced by Chardin, Daumier and Samuel Palmer. She also made illustrations for Westminster Synagogue and for a number of book jackets including Carson McCullers Reflections In A Golden Eye (The Cresset Press, London, 1958).

Ruth Collet died on her 92nd birthday in Middlesex, England in 2001. A memorial exhibition was held in 2003 at the Broughton House Gallery in Cambridge. Her work is held in UK public collections including the Ben Uri Collection and the University of Edinburgh.