As the Museum's press release, linked above, points out, the Triptych
was produced in an era of postwar art [the early 1970s] when minimalism, video art, and and installation dominated the New York scene. At the time, figuration, and even painting itself were out of fashion.Mr. Dinnerstein's email gives a link to "Triptychs and Temporality." an article, from the Journal of the National Academy of Art and Design, by Larry Silver, Farquhar Professor Emeritus of the History of Art at the University of Pennsylvania. Professor Silver discusses the references to historical artistic styles and artists that appear in the Triptych, with illustrations that focus on details of the painting.
I had the pleasure of meeting Simon Dinnerstein twice. The first time was after he gave a talk about the Triptych at the Brooklyn Historical Society. The second was when, at the suggestion of my friend Louise Crawford, I visited his home and studio in Park Slope, Brooklyn, and took the photo shown above. The story of that visit, along with those of mine with six other artists over a two day span, is here.