Abstract Reliable knowledge of the complex X-ray form factor and the photoelectric attenuation coefficient is required for crystallography, medical diagnosis, radiation safety and XAFS studies. Discrepancies between currently used theoretical approaches of 200% exist for numerous elements for X-ray energies from 1 to 3 keV. This work addresses key discrepancies and derives theoretical results in near-edge soft X-ray regions. DHF wave functions are employed and computational and convergence issues are of direct concern. Comparisons with simpler wave functions, including additional relativistic corrections to the form factors, are insightful. The current result improves upon the theoretical uncertainty in these regions to an estimated standard deviation of 20–30%.