Abstract: For manufacturing security documents, a plurality of security documents are printed on a sheet. The sheets are being processed in batches (15a, 15b). Each sheet carries a unique, machine readable identifier. During manufacturing, the batches are processed by several printing stations (10). At each printing station, the identifiers are read by a local computer (13) attributed to the printing station. The results are transferred upon request in data packets to a central data base (16). Each data packet contains the information for several sheets, which obviates the need to transfer the corresponding data in real time over the network. To increase security and decrease network dependence, each local computer is equipped with apparatus to check the processing status of a batch autonomously.