Abstract: A process for initiating a premature roll change of a web to be unwound from a roll wound on a spool, the process including the steps of measuring temperature at an end of the roll in a zone up to 150 mm away from a surface of the spool in a radial direction during a time that the roll has between 100% and 60% of its fully wound weight, using a non-contact measuring device, determining a radial distance from the spool surface when a temperature difference.gtoreq.0.5.degree. C. is found between temperature measurement locations in the zone and cooler adjacent areas, and storing the determined distance for triggering a signal that initiates a replacement of the roll when that distance is reached.