A gadget lover, Salomon put a camera inside a briefcase and fitted levers to trip the shutter and wind the film. He took this hidden camera into a courtroom and photographed a murder trial. The photographs from the trial sold so well that he quit Ullstein and went to work full time as a freelance photographer.
He specialized in photographing meetings, conferences and social gatherings without the use of supplemental light. He was the first European photographer to work in the White House. He published a book of his candid photographs of more than 170 famous people.
During the Nazi regime he left to go to Holland with his family. When Holland fell, he went into hiding, but was betrayed by a Dutch Nazi. Salomon was last seen on May 24, 1944 en route to the concentration camp at Auschwitz.