Unlike them, however, he preferred to make small works and tended to explicitly draw upon natural forms and figures for his abstract subjects.

[10][11][note 2] In May 1930 Reiss selected a drawing by Rosenborg to be shown in an exhibition of creative design by City high school students.

[5][12][note 3] From 1930 to 1933, aged 17 to 20, Rosenborg studied with Reiss in what Vivian Raynor of the New York Times called a "pupil-apprentice" relationship.

[1] In April 1934 Rosenborg was one of 1,500 artists to participate in the annual Salons of America exhibition, which was held that year in Rockefeller Center's RCA Building.

[note 11] During this period Rosenborg began an association with an art dealer, Marian Guthrie Willard, that would last into the war years.

Throughout his career his work appeared in both group and solo shows in a wide variety of galleries and museums both in New York and elsewhere in the United States.

Tumultuous seascapes, serene landscapes, and brightly colored floral still lifes, were all executed with an attention to richly textured, heavily painted surfaces.

[1] Unlike better-known abstract expressionists, Rosenborg made small paintings and gave preference to gouaches and watercolors over oils.

[44] Writing of a solo show held at the Landry Gallery in October 1960, Stuart Preston of the New York Times said, "The essence of mystery and magic is exactly what distinguishes Ralph Rosenborg's meditative semi-abstract landscape water-colors...

[49] Writing about the same show, Bennett Schiff, critic for the New York Post, said "A mystical intensity and a beauty which burns in ruby and sapphire colors are in these fine paintings.

Between 1936 and 1938 he taught classes at the Brooklyn Institute of Arts and Sciences and subsequently served as a guard for a year or two at the Museum of Non-Objective Painting.

[3] Throughout his career he was thought to have relied on the women in his life for economic as well as emotional support—first his mother, then Louise Nevelson, with whom he had a passionate relationship between 1942 and 1948, then, briefly, her sister, Anita, and finally, his wife, Margaret, after they met in 1949 and married in 1951.

[63]: 150  According to Nevelson's biographer, "Rosenborg's gifts as a painter were undermined by his alcoholism, irascible temper, and adolescent-like quest for independence..."[63]: 151  Another writer said he had an "exasperating character" and was "a legend in the art world for his suspicion of anything smacking of entanglement in social or professional relationships.