A method for calibrating a first image processing apparatus at a first location with a control image processing apparatus at a second location. The method comprises obtaining a plurality of individual exposure levels and plotting them against time creating a deviation history and comparing it to the operating specification for the control image processing apparatus. If the deviation history is within the operating specification, initiate a calibration, if not adjust the exposure levels and then initiate calibration. The calibration comprises preparing a calibration curve of exposure level versus density for a plurality of shipped thermal donors; computing an exposure modification curve by comparing a control thermal receiver to the shipped thermal receivers; transmitting the calibration and then the exposure modification curve to the first image processing apparatus; and adjusting the first image processing apparatus exposure levels to conform to the calibration curve and the exposure modification curve.