American artist Helen Frankenthaler (December 12, 1928-December 27, 2011) developed a technique of thinning pigments with turpentine so they soaked into and stained the unprimed canvas instead of resting on the surface.
Biography on Wikipedia: https://en.wikipedia.org/wiki/Helen_Frankenthaler
Jacob’s Ladder by Helen Frankenthaler
1957 / Oil on canvas / 113-3/8″x69-7/8″ / Museum of Modern Art, NYC
Helen Frankenthaler on Artnet: http://www.artnet.com/artists/helen-frankenthaler/
Further reading:
https://www.frankenthalerfoundation.org/
https://jwa.org/encyclopedia/article/frankenthaler-helen
https://artuk.org/discover/stories/the-radical-beauty-of-helen-frankenthalers-woodcuts
https://www.skowheganart.org/helen-frankenthaler