The camera was made of brass and was not much bigger than a fist. Inside it were small pieces of X-ray film. At King’s College London, Rosalind Franklin and her student Raymond Gosling put a thin fibre of DNA in front of a small hole in the camera. Then they sent a narrow beam of X-rays into it, for hours or even days, to make one picture. In the spring of 1952, one of these pictures was the clearest they had ever made. But it had a problem. The film inside the camera had moved, so the pattern was not in the centre and one edge was cut off.
This picture was called Photograph 49. On the same day that Franklin saw it, she started a new picture of the same sample. That one became Photograph 51, the most famous picture in the history of molecular biology. For more than fifty years, people said that Franklin did not understand her own picture. A new paper, published on 5 October 2026 in the Journal of the History of Biology, says the opposite. Its evidence is the forgotten photograph that came first.
Most of the old story comes from James Watson. He said that in 1953 Maurice Wilkins showed him one of Franklin’s photographs, and he suddenly understood something important. He wrote that his mouth fell open and his heart began to beat fast when he saw it. In his 1968 book, The Double Helix, he wrote that the black cross in the picture could only come from a helix, which is a spiral shape.
The new paper was written by Alistair Sponsel, a historian of science at the Science History Institute in Philadelphia, and Brian Sutton of King’s College London. They say that Photograph 51 showed a helix so clearly because Franklin wanted it to.
Franklin usually wrote careful notes in the lab, but she wrote very little about Photograph 51. So Sponsel and Sutton looked at Photograph 49 instead. They found that Franklin had written many notes about it. In their view, she knew that this earlier picture showed a helix, and that is exactly why she made a second, better one. They believe Photograph 51 was made to be published. It was not a test picture that Franklin thought was unimportant.
This fits what other scientists say about her. The scientist Elspeth Garman says Franklin “was an experimental perfectionist.” A picture with a cut edge was good enough to teach Franklin something. It was not good enough to show to other people.
So why did she not publish quickly? Franklin chose to work slowly. In 1952, she and Gosling studied their pictures with long and difficult mathematics. She did not want to build models of DNA before she had the data. She said they would wait and let the spots on the photograph tell them the structure. By February 1953, her notebook shows, she was thinking about a helix, but she was not sure how many strands it had. A draft of her paper from 17 March 1953 shows that she had already found the correct structure. The next day, news of Watson and Crick’s model from Cambridge arrived at King’s.
On 25 April 1953, the journal Nature published three papers about the structure of DNA. Watson and Crick’s paper mentioned Franklin only in a short note at the bottom of the page. Papers by Wilkins and by Franklin came second and third. Later, Watson and Crick said that without Franklin’s data, finding their structure would have been very unlikely, maybe impossible.
Franklin died of ovarian cancer in 1958, when she was 37. In 1962, Crick, Watson and Wilkins won the Nobel Prize. The prize is never given to people who have died. Only in 1999 did Watson say that the Franklin photograph was “the key event.”
The physicist and historian Robert Crease once went to a series of talks by Watson at Brookhaven National Laboratory. After the first talk, there was time for one question. A woman raised her hand. She asked Watson to say a little more about what Rosalind Franklin did for the discovery of DNA. Some people in the room clapped.