A Digital Proof (Contract Proof) is an ISO certified test equipment for the graphics industry. A digital proof simulates the color of offset printing or gravure printing color accurate binding within the tight tolerances of ISO 12647-7. Today, a digital proof is processed via a RIP and then produced with pigment inkjet printers on special proofing papers.
The proof data is converted to color separations, then reassembled into a composite image to simulate overprinting and trapping correctly. The data is then passed as a composite image to a usually more than 8-color inkjet printer, which prints the data. In addition to the proof data, a digital proof must carry a Mediawedge by UGRA / FOGRA or IDEAlliance to be legally binding. Thanks to the standardized mediawedge, the print shop is able to check the proof for correctness. Since many printers don’t have the neccessary metrology at hand, digital proofs are often directly provided with a test report, which documents the accuracy of the measured values of the media wedge directly on the proof.
Older proofing methods as chromalin or Kodak Approval etc. are today hardly any more found in the market.
In addition to the term “digital proof” even terms like color proofing, proofing or online proofing are common.
In the ISO 12647 “Contact Proofs” (ISO 12647-7) are the highest standard of proofs, but the term “Validation Prints” (ISO 12647-8) is also defined. A “Validation Print” is distinguished in that it is less accurate in color, but therefore can also be produced on laser printers. Compared to the contract proof, a Validation Print has higher color variations and is NOT automatically legally binding – only after prior consultation. A real “proof”, ie a real contract proof according to ISO 12647-7 is currently not only the most color accurate and best option, but also the only legally binding proof.
What is a proof?
A proof (correct: contract proof) is an ISO-certified testing device for the graphic arts industry. A proof simulates the colourfulness of offset or gravure printing in a colour and legally binding manner within the narrow tolerances of ISO 12647-7. Today, it is almost exclusively calculated using a RIP and then produced with inkjet printers on special proof papers.
The proof data is converted into separations, then reassembled into a composite image to correctly simulate overprinting and trapping. The data is then transferred as a newly created composite image to an inkjet printer, usually with more than 8 colours, which prints the data. In addition to the print data, a proof must also carry a UGRA/Fogra media wedge in order to be color-consistent and legally binding. Thanks to the standardised wedge, the printer is able to check the proof for correctness. Since many printing companies do not have this measuring technique at hand, the proof is often provided directly with a test report that shows the correctness of the measured values of the media wedge directly on the proof.
Earlier methods such as Chromalin etc. are no longer available on the market today.
In addition to the term “proof”, terms such as colour proof or digital proof are also commonly used.
ISO 12647 defines the term “Validation Print” (ISO 12647-8) in addition to the highest standard of contract proof, “Proof” (ISO 12647-7). The Validation Print is characterized by the fact that although it is less accurate in color, it can also be produced on laser printers. Compared to the contract proof, however, it accepts much higher colour deviations and is only legally binding after prior consultation. A real “proof”, i.e. a real contract proof according to ISO 12647-7 is currently not only by far the best variant in terms of colour, but also the only legally binding proof.
Further information: https://en.wikipedia.org/wiki/Prepress_proofing