The processing of diffraction data taken on a screenless Weissenberg camera for macromolecular crystallography

A method has been developed based on Rossmann's [J. Appl Cryst. (1979). 12, 225-238] treatment of oscillation camera data for processing of X-ray diffraction data collected on a screenless Weissenberg camera for macromolecular crystals [Sakabe (1983). J. Appl. Cryst. 16, 542-547]. Crystal orientation parameters and film orientation parameters are refined by minimizing the discrepancies between the calculated and observed positions of reflections on a film. A data processing example is presented. Intensities were collected using a synchrotron radiation source and the imaging plate as a detector. The results show that the quality of the data is good, as judged by the agreement of the equivalent reflections. An absorption correction based on the use of the empirical Fourier expansion method reduced the R value and improved the correlations between Bijvoet differences observed on the different imaging plate exposures.