Why are reflections on different scales?
Various physical factors lead to observed intensities being on different scales. Scaling models should if possible parameterise the experiment so different experiments may require different models
Understanding the effect of these factors allows a sensible design of correction and an understanding of what can go wrong
(a) Factors related to incident beam and the camera
(b) Factors related to the crystal and the diffracted beam
(c) Factors related to the detector