Ray Gosling's (2012) account of how Franklin gave Photo 51 to Wilkins (p. 182)

    "Even before the stunning revelation of Watson and Crick's model of NaDNA at the Cavendish the atmosphere at King's had become one of suppressed turbulence due to the tension between Rosalind and Maurice. Randall has reluctantly taken the view that Rosalind should leave King's. For her part, Rosalind had already had discussions with Bernal, at Birkbeck, with a view to her working on the structure of tobacco mosaic virus. Randall made possible the smooth transfer of her Turner-Newell fellowship and set March 1953 as the time for her departure.

    Rosalind and I were working hard on calculating the Patterson function of the A structure, despite Randall's edict that she should cease all work on DNA [NB: letter dated 17 April 1953]. This was an impossible ban since we had so much to write up. Indeed, we were putting the finishing touches to two papers to Acta Crystallographica in January 1953. It was then that Rosalind realized, with regard to structure B, that she would not have time to go beyond the draft analysis which we had already started and was published as the third paper in the triumvirate in Nature April 1953. She therefore decided to make a "present" to Maurice of the original film of our best structure B diffraction pattern, the 51st exposure in our series of X-rays of single fibre specimens held as various steady humidities.

    Accordingly, I went down the corridor to Maurice's lab/office, sometime in January 1953 [on DATE] and gave him this beautiful negative. He was very surprised and wanted reassurance that Rosalind was actually saying he could make whatever use he wished of this interesting data. This, of course, confirmed the belief of Alex Stokes and himself that the structure was helical. In this respect, after sight of the Watson and Crick model [on DATE], Rosalind changed her mind, especially in view of the X-ray equivalence of the hydrogen bonded specific paired bases, and admitted that structure A must also contain helical units.

    In spite of Randall's edict, Rosalind and I set about making a vector difference map with our Patterson data, which to our great satisfaction and delight, fitted well with a two chain helical symmetric unit."


Maurice Wilkins in his autobiography states (as quoted in the reference below):

"One day in January [inferred as Jan 30] 1953, Raymond met me in the corridor and handed mean excellent B pattern that Rosalind and he had taken. For me to be shown raw data in this way was quite without precedent and, even more extraordinary, Raymond made it clear that I was to keep the photograph .... I had recently been relieved to hear that Rosalind was going to leave our lab for a post at Birkbeck College and was finishing up her work. I assumed that my being shown the pattern was connected with her plans to leave, and she was handing over the data so that we follow up on what she and Raymond had done. Raymond gave me to understand that Rosalind was handing the to me to use as I wished."

From JD Watson (2012). The Annotated and Illustrated Double Helix (A. Gann & J. Witkowski, eds.) Simon & Schuster.