Rosalind Franklin produced X-ray diffraction evidence that helped reveal DNA’s structure, including the famous image known as Photo 51. The image was made in 1952 by Franklin’s PhD student Raymond Gosling under her supervision at King’s College London.
Franklin’s DNA work used X-ray crystallography, a method that records how X-rays scatter when they pass through an ordered biological sample. The diffraction pattern from Photo 51 strongly indicated that DNA had a helical structure. Her measurements also helped establish important dimensions of the molecule and the placement of phosphate groups.
James Watson and Francis Crick used experimental evidence from Franklin and others while building their 1953 DNA model. Franklin did not share their 1962 Nobel Prize, partly because she died in 1958 and Nobel Prizes are not awarded posthumously.
Franklin later made major contributions to the study of viruses, including tobacco mosaic virus. She is sometimes described as having photographed DNA directly, but Photo 51 was a diffraction image rather than an ordinary photograph.