Technique of Intensity Measurements in X-ray Crystal Analysis by Photographic Methods

Various important points of technique in photographic X-ray intensity estimation are described. Many of these points are equally important whether the intensities are finally obtained by visual estimate or by measurement with some form of integrating photometer. Indeed, the value of long and tedious photometer integrations is sometimes wasted unless these points are carefully observed. Matters dealt with include spectrometer requirements for the preparation of reliable photographic records; methods for correlating the intensities over the range of several thousand to one required for detailed structural investigation; multiple film technique and development processes; the calibration of films and the integration of intensities; and finally the absolute measurement of intensities photographically by means of calibration with standard crystals.