Before printing a complete batch the print image is verified with the proof print on the proof press. Very different criteria are taken into account here, depending on the print product. In gravure colour binding proofs are produced on the proof press to verify a match to the target proof or contract proof. Proof prints are also possible in offset printing in principle, but in practice are hardly used due to the high level of standardisation. No colour-binding proof prints are produced in advance in flexo printing. The proof print is only used for a technical-content verification of the printing form. Colour adjustment relative to the target proof or contract proof occurs exclusively on the printing press.