Zimmerman developed an experimental method of teaching drawing from memory or the "visual imagination." He was the first drawing teacher of Boston Expressionists Hyman Bloom and Jack Levine in ca. 1928-1929. Denman Ross, an influential educator, art collector and painter, became the instructor and patron of Bloom and Levine shortly after he wrote his essay on Zimmerman's experiment in art teaching.
From the description of Harold K. Zimmerman papers, l930-1954. (Unknown). WorldCat record id: 122502883