1. A method for operating a web printing system comprising: identifying a temperature change for at least one roller in a web printing system; identifying a temperature change for a web moving through the web printing system at one or more locations in the web printing system; modifying web velocity computations for a reflex registration system with reference to the identified temperature change for the at least one roller and the identified temperature change for the web; and operating printheads to eject ink onto the web at positions identified with reference to the modified web velocity computations.