Marsh began to work with John Steuart Curry after his training with Miller. Both Marsh and Curry took lessons from Jacques Maroger, whom Marsh met in New York City in 1940. Maroger, who was a former restorer at the Louvre, believed he had discovered the secrets of the old masters and was well known for his advocacy of a painting medium made by cooking white lead in linseed oil. Maroger provided a body of material documenting his work for Marsh and Curry to study, and they adopted his ideas.