On the treatment of protein data measured on the oscillation camera

The method used in Oxford for the collection and reduction of protein data from the Arndt-Wonacott oscillation camera [Arndt, Champness, Phizackerley & Wonacott (1973). J. Appl. Cryst. 6, 457-463] is described. The photographs are digitized with an Optronics Photoscan P-1000 drum scanner operated in an off-line mode, and the magnetic tapes are subsequently processed on an ICL 1906A computer. Results are presented for the protein phosphorylase b. The estimation of standard deviations for both fully and partially recorded observations is discussed, and the intensities for these two categories of term are compared.