Myrrha Dagmar Dub was born in Zurich, Switzerland, and grew up in Italy. Between 1930 and 1936 she began her drawing practice through free art courses. In 1937, she entered the Università Cattolica del Sacro Cuore and studied philosophy. With the rise of fascism and anti-Semitism at the beginning of World War II (1939-1945), she was forced to abandon her studies due to a decree that prohibited the enrollment of foreign Jews in higher schools. In 1939, she left Italy and moved continuously throughout Europe in a poorly documented period of her history, passing through Bulgaria, Hungary, Vienna, Croatia, and Slovenia.
In 1944, she moved to Rome with her husband, Croatian Jossip Hargesheimer. She worked for the International Organization for Refugees, which directed the emigration of so-called "war-displaced" people to countries in the Americas. Schendel and Jossip left, in 1949, for Porto Alegre. In Brazil, she devoted herself to artistic studies and produced drawings, sculptures, and ceramics. She dedicated herself entirely to painting from 1950 on, a practice that, according to the artist, imposed itself on her as a matter of life or death. In this phase, the influence of Giorgio Morandi (1890-1964) on the themes and palettes of the canvases is remarkable.
In 1951, her participation in the 1st São Paulo International Biennial allowed international affiliations and her insertion into the contemporary art scene. In 1953, she moved to São Paulo and adopted the last name Schendel. During her first years in the city, she became close to the circle of thinkers who would soon become her friends and first critics: Mário Schenberg (1914-1990), Haroldo de Campos (1929-2003), Theon Spanudis (1915-1986) and Vilém Flusser (1920-1991). In 1955, she participated in the 3rd São Paulo International Biennial.
In the 1960s, her work turned to more abstract and less figurative investigations. When she was presented with an enormous quantity of Japanese rice paper, she embarked on a series of experiments with the material. In 1964, she began the Monotipias [Monotypes] series, in which she drew peculiarly on rice paper. In 1966, she started the series Droguinhas [Little Nothings], made with twisted and braided rice paper. In 1967, she used acrylic as support and presented the series Objetos Gráficos [Graphic Objects] and Toquinhos [Little Stubs]. In 1968, she participated in the 34th Venice Biennale, in Italy.
Throughout the 1970s, she continued her investigations into the process of "transparentization" of the world and of time. In 1974 she created the series Datiloscritos in which she "drew" (typed) letters, signs, words, and sentences with a large cylinder typewriter. In the 1980s, she vigorously recovered her interest in painting and produced the white and black tempera, the Sarrafos, and began a series of paintings with brick dust and gold.
After her death, several exhibitions presented her work in Brazil and abroad, and in 1994 the 22nd São Paulo International Biennial dedicated a special room to her work. In 1997, the art dealer Paulo Figueiredo donated many of the artist's works to the MAM-SP – Museu de Arte Moderna de São Paulo [Museum of Modern Art of São Paulo]. In 2007, her works participated in documenta 12, in Kassel, Germany. Among her most recent exhibitions are solo shows at Jeu de Paume, Paris (2001); Tate Modern, London (2013); and Pinacoteca do Estado de São Paulo (2014).