US Patent 7152941 Printing system calibration

In an implementation of printing system calibration, a calibration system measures colorant levels of a colorant applied to a test element, measures color values of the colorant applied to a print media after the colorant is in the finished state, and establishes a correlation between the measured colorant levels and the measured color values. Further, the calibration system converts the measured colorant levels to corresponding predicted color values based on the correlation, compares the predicted color values to target color values, and calibrates a print unit if a difference between the predicted color values and the target color values exceeds a threshold value.