Rosalind Franklin started working at King’s College London in 1951. She began there in January as a research associate in the Medical Research Council’s Biophysics Unit, directed by John Randall.
Franklin was initially expected to investigate the structure of proteins and lipids in solution. Randall redirected her toward DNA fibres, where her expertise in X-ray diffraction made her particularly valuable. Raymond Gosling, a graduate student already working on DNA, became her assistant.
During her time at King’s, Franklin produced groundbreaking diffraction data on DNA’s A and B forms. Gosling took Photo 51 in 1952, and Franklin’s analyses helped establish that DNA had a helical structure. She left King’s in March 1953 for Birkbeck College, where she shifted her attention to viruses, especially tobacco mosaic virus. The years 1952 and 1953 are common mix-ups: they mark major DNA milestones, but not the start of her King’s appointment.