A printer control system (101) comprising a processor (104) and processor accessible memory (103), the processor (104) being adapted to control the memory (103) to store a concordance between substrate identities for different identified substrates and print control data to be used by the print control system (101) in controlling a printer to control colour and/or quality when printing upon identified substrates, the processor (104) being adapted to associate at least one first identified substrate with the same print control data used for a second, different, identified substrate.