1. A method of performing print engine calibration comprising: creating a color space conversion equation for a scanner of a class of printing devices; printing first test patches on a first sheet using a previously established master tone reproduction curve (TRC) relating to a master aim curve for said class of printing devices using a printing engine of said a printing device within said class of printing devices; scanning said first test patches using a scanner of said printing device to produce a first scanned RGB value for each first test patch; converting each said first scanned RGB value to an XYZ pseudo space using said color space conversion equation to produce first XYZ values; comparing said first XYZ values to second XYZ values of white paper to generate DeltaE curves for each of said first test patches relative to white paper; interpolating said DeltaE curves to form an equivalent aim curve; and after said equivalent aim curve is determined, periodically calibrating any printing device that is within said class of printing devices using said color space conversion equation to produce second XYZ values and producing a resulting TRC for said second XYZ values based on said equivalent aim curve.