What is disclosed is a method for maintaining consistent color output
across printers even when the inline sensors have differences in accuracy
due to various technical and environmental factors. A spectrophotometer
is used to measure the color quality of printed references. Adjustments
are then iteratively made until reference charts of desired color quality
are obtained. The printed reference allows one to achieve relatively high
system performance by removing sensor inaccuracies. Using the printed
reference measured by the inline sensor control systems of each machine
are calibrated. At customer sites and at suitable intervals, a reference
document can be read using the inline sensor on a reference machine and
any differences from expected values can be calibrated out. The present
method is also applicable to other color management functions such as
memory color and automatic profile generations using inline/offline
sensors and can be used for determining reference values while
calibrating control systems of printers over a wide range of
applications.