The role of normal absorption in x‐ray diffraction measurements of integrated Bragg intensities from epitaxial (or other) layers and their associated substrates is discussed in terms of the transmission factor. It is shown that the technique for the determination of the polarity of an epitaxial layer by means of anomalous scattering of x rays need not be limited to the case of an effectively infinite layer thickness, in Bragg geometry. Some discussion of layer‐thickness determination is also given.