Abstract: A method and apparatus for maintaining correlation between the parts of a film processing order from its receipt in a lab to its assembly for return to the customer includes placing a machine-readable identifier on the film, envelope and prints. The identifiers are read at the point of final order assembly and if any identifiers are not readable an error counter is incremented. If the error counter reaches a predetermined maximum number, an alarm is given and the operation is halted for operator intervention. If the maximum error number is not reached, the identifiers read at the finishing station are compared for equality. If there is a mismatch between identifiers, an alarm is given and the operation halted for operator intervention. Each time an order is successfully processed with no misreads, the error counter is decremented by some predetermined number. In a predetermined embodiment, the error counter is reset after each operation intervention.