Projective properties of Laue topographs

White beam or transmission Laue X-ray topography is a now widely used imaging technique, especially in association with synchrotron sources. Several images may be recorded simultaneously, potentially allowing for direct defect characterization. Owing, however, to projection conditions, these images suffer from rather large geometrical distortions. This paper presents a general treatment of the projective properties of Laue topographs. Specific results applicable to a simple but frequently utilized specimen-detector geometry are also given. An example serves to demonstrate the usefulness of such calculations in the interpretation of experimental results.