Untitled (Black on Grey) is a 1970 acrylic on canvas painting by Mark Rothko, featuring a black rectangle and a grey rectangle.

In mid-1968, Rothko suffered an aortic aneurysm and could only work on stretched paper during his recuperation.

The edges were secured using gummed tape that left a white margin when removed.

Later, Rothko taped the edges of his canvases before painting to produce the same effect.

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