In September 1931 the call went out to like minded medical photographers to gather at Yale University in New Haven, Connecticut. More than 30 people were in attendance, to the surprise of many there were six women. One of these six women was Stella Zimmer. In a career change from x-ray technician to medical photographer, a move that would alter her life, she became an influential member of the Biological Photographic Association.

In the early 1930s she sought out informal training with Louis Schmidt at Rockefeller Institute of Research in New York City, NY. At the time this was only a research lab, but Schmidt did not turn Stella away. In six weeks she returned to Syracuse University with the knowledge and determination to build a photographic department. Zimmer then became the Director of Medical Photography. Her expertise in photography and photomicrography became well known among her peers.

Stella was a charter member of the board of directors and held that position until 1955. She was treasurer from 1935 to 1951. By 1950, she had already obtained her fellowship, and received the Louis Schmidt Award, then known as Annual Award.

Three women who have influenced the BPA for many years view the 1972 Salon – Stella Zimmer, Anne Shiras and Marie Ikenberg Lindberg.

Her organizational skills in maintaining written and photographic records of the BPA lead to the creation of Historical Committee which she chaired until her retirement in 1966.

As a retiree, Stella had an active life. She kept in touch with fellow BPA pioneers and a large circle of friends.