Diminished intensity defects occur in electrostatic printing between image regions having grey levels, i.e., different electrostatic potential and toner densities. Such defects occur when higher density regions "steal" toner from lower density regions. The system and methods according to this invention compensate for these defects by modifying the input image data. The input image data in lighter regions that precede or occur near a light-to-dark transition to a dark region are raised above the input image values. Thus, when printed, the printed image intensity values in such regions are higher than the corresponding image intensity values. As a result, when the higher density regions steal the extra toner provided due to the raised values, the gray level of the printed image corresponds to the desired gray level. The magnitude of these defects is periodically measured with a calibration pattern to generate and/or update compensation factors used in the compensation process.