Photographs: Jewish Museum Berlin

BERLIN — His left arm extended, the man in the photograph above holds out a bar of soap. His right hand is clasped over his heart. His mouth is opened, as if he were singing an aria about the virtues of Gardenia, the “real toilet soap” he is hawking to passers-by.

Both the image and its maker had fallen into obscurity. Born in what is now Poland in 1899 to a family of German Jews, Ruth Jacobi spent some years in Berlin then permanently immigrated to the United States in 1935. She spent decades living quietly as a doctor’s wife in Astoria, Queens, and abandoned the craft of photography for which her sister, Lotte Jacobi, became famous. Then, in 2004, Aubrey Pomerance, the chief archivist at the Jewish Museum Berlin, learned that a trove of photographs by the lesser-known Ms. Jacobi, who died in 1995 and had no children, lay in storage with a relative in Mission Viejo, Calif.

Mr. Pomerance arranged for the museum to acquire much of the collection — some 800 prints and 3,000 negatives — in 2005. And after several more years of research and preparation, he mounted an exhibition of around 70 images, “Ruth Jacobi: Photographs,” that went on view on Nov. 7. The exhibit closed on Sunday — it had already been extended by a month — but Mr. Pomerance hopes to find an American institution to put on the show.

Ms. Jacobi’s family had been in the photography business for three generations; her great-grandfather, family lore has it, studied with Louis Daguerre, the photographic pioneer who invented the Daguerreotype process. Ruth was trained at the Lette-Verein photographic school for women, and after five years working in her family’s Berlin studio, she traveled to the United States in 1928, joining a husband, Hans Richter, whom she had married two years earlier.

“It was a very unhappy marriage, probably on the brink of separation, but he talked her into a new beginning,” Mr. Pomerance said. “They went to New York together, where she tried to find a job as a photographer and did a lot of menial jobs.” At various points she worked as a cook and at a photo agency. She met with Alfred Stieglitz, who was instrumental in securing photography’s acceptance as an art form and who gave Ms. Jacobi encouragement.

I was struck by Ruth Jacobi’s images on a recent vacation in Berlin during a visit to the museum, which was designed by Daniel Libeskind and opened in September 2001 (two days before the 9/11 attacks). The works evoked other famous images of early 20th-century life on the Lower East Side — like those made by Helen Levitt and Rebecca Lepkoff — but with a different sensibility and mood.

The Lower East Side photographs documented street life among the Eastern European Jewish immigrants who had made the neighborhood one of the most densely populated urban quarters anywhere in the world. Several of the images are of vendors, selling pretzels, herring, cloth, shoes, fruit and other goods. Other images show Union Square, the docks and a window-washer. One of the most enigmatic — and humorous — images shows a well-dressed woman walking down a sidewalk, holding a goose by a leash. The woman and the goose are in the same position — striding forward, right foot forward.

Ms. Jacobi returned to Berlin in 1930, and from 1931 ran her family’s photography studio with her sister, Lotte, who was three years older and would eventually became famous as a portraitist of cultural, literary and artistic figures like Berenice Abbott, Marc Chagall, Robert Frost, Paul Robeson, J. D. Salinger, Edward Steichen and Stieglitz.

The sisters opened a photography studio together in New York in September 1935. But they parted ways in 1936. Ruth Jacobi abandoned photography a few years later, and instead devoted her time to her second husband, Morris Roth, a Hungarian-born physician she met in 1935. They lived in Astoria until his death in 1972, then she lived on West 66th Street until moving to southern California around 1987.

Interestingly, the image by Ruth Jacobi that has probably been the most widely published and seen is a portrait of her sister, who died in 1990.

“Ruth published hardly any pictures of her own, under her own name,” Mr. Pomerance said.

One notable exception was the use of Ruth’s images for the dust jacket of Michael Gold’s best-selling novel “Jews Without Money,” published in 1930 in the United States and in Germany in 1931. The jacket was designed by John Heartfield, a pioneer of photomontage who was known for his criticisms of both the Weimar Republic and the Nazi regime that replaced it.

Mr. Pomerance said the first reaction of many of the visitors to the exhibition was surprise that Lotte Jacobi had a sister. More than that, he said he hoped the exhibition would revive interest in an accomplished photographer whose career, though relatively brief, provided an important glimpse at life in Europe and New York in the fateful years before the Second World War.

“I think what we’ve done is put Ruth Jacobi on the map,” he said. “You can’t think of the Atelier Jacobi anymore without Ruth.”