Reta studied at the Banff School of Fine Arts in the summers of 1941–44, where Walter J. Phillips taught her watercolor techniques.

[1] Bornstein taught Reta Cowley to use form and color to structure her paintings and to pattern her brush strokes.

Cowley's watercolor style had matured by the late 1960s, one in which she depicted the landscapes of the prairies in terms of their unique qualities of light and space.

[4] Clement Greenberg wrote, "Among the outspokenly representational painters of merit in Saskatoon was Reta Cowley, who renders the villages and towns of central Saskatchewan with delicacy and fresh feeling, She demonstrates that one can learn from Cézanne and Klee how to make nature more, not less, vivid in pictorial art.

"[5] In 1949 Reta Cowley wrote for an art school scrapbook, "Let us carry back with us into everyday life some of the strength and serenity of the woods.

Memories of the peace and beauty of our northland can fill a corner of our mind to which we can withdraw for renewed courage when times are difficult.