Abstract: The beginning of a web material fed to a processing device and stored in the form of a roll on a core is provided with a machine readable code which represents an identification code for the web material as well as property data relevant for the processing of the web material. The identification code and the property data are read in at the beginning of the processing of the web material and only web materials with valid identification code are admitted for processing. The processing device is adjusted to the web material used by way of the read in property data. At termination of the processing, the identification code and the updated property data of the web material are again recorded in machine readable code onto the beginning of the remaining web material so that they are again available for the next processing procedure.