A system, apparatus and method are provided for adjusting an on-line appearance sensor system (OnLASS) for color and other appearance characteristic(s) of a web product produced during a production run of a web production system. The OnLASS is calibrated and its setting(s) are sent to a color error minimizer (CEM). The OnLASS measures a first appearance characteristic of the web product during the production run and the on-line measurement is sent to the CEM. After the production run, a second appearance characteristic of the web product is measured with an off-line appearance sensor system (OffLASS) and the off-line measurement is sent to the CEM. The CEM compares the on-line and off-line appearance measurements and adjusts at least one setting based on the comparison. The adjusted setting(s) are sent to the OnLASS.