An apparatus for marking a film copy includes a mapper and a coder. The mapper maps a print identifier to be associated with the film copy into a serial number comprising a sequence of J numbers. The coder creates at least two-error correcting numbers, e.g. Y and Z, as a function of one, or more, of the J numbers. The film copy is then marked in accordance with L numbers, which comprise at least the two-error correcting numbers Y and Z.