New York City, 3 (unfinished)

The red, blue and yellow bands crossing this canvas are strips of adhesive tape. That is how Mondrian worked once he was in New York. Tape could be lifted, moved a few millimetres and pressed down again, so a picture would hang on his studio wall for months while he kept adjusting it. Painting the strips in properly was meant to be the last step, and in the whole New York group he got that far with one canvas only. This one had been begun in Europe, probably around 1938, and crossed the Atlantic with 16 others when he left London in 1940. It was still taped, and still on the wall of his studio on 59th Street, when he died in February 1944. In 1977 the painter Harry Holtzman, who looked after his estate, and the restorer Bill Steeves pressed the loose strips back down and replaced the torn ones, matching the colours and leaving the arrangement as it was.