DiffractIndex (created in Guide) imports tif, jpg, bmp or dm* (Digital Micrograph) files for analysis of diffraction ring diameters in 2D diffraction patterns. DiffractIndex calculates diffraction ring centres and the pattern centre to output ring radii in Å given that pixel size calibration is performed. DiffractIndex can be used to calibrate pixel size by using a known standard diffraction pattern. The program also generates a 1D diffractogram by azimuthally integrating (caking) the diffraction pattern. See the pdf file for full documentation.