I recently received a digital proof for a small poetry book I had designed for a client. The following paragraphs describe the items I looked for in checking the proof. You may want to take a similar approach in reviewing your proofs.
The Proofing Method
First of all, my proof was a single copy produced on an HP Indigo press as a prototype for a longer press run. The Indigo is a xerographic digital press. Think “ultra-high-end color xerox.” The commercial printer produced the proof on this equipment because the rest of the run would also be produced on this press. It was a prototype, exactly matching the remainder of the run.
In your case, you may (or may not) be printing via offset lithography instead of digital technology. If this is true, you will most likely receive an inkjet proof instead of a xerographic proof. In either case your custom printing vendor will have “fingerprinted” the proof to the final press output. That is, the two will match as closely as possible. In the first case, the digital xerographic proof from the Indigo is exactly the same as all successive copies of the press run. In the case of the offset job, the inkjet proof closely resembles the final output from the offset press.
The Substrate Used for the Proof
“Substrate” is printer’s lingo for the paper on which the job will be produced. If you are printing a digital job on an Indigo or other xerographic press, you can request that your commercial printer produce the proof on the exact stock on which the final job will be printed. This is prudent. For instance, if you decide at the proof stage that the job would look better on a coated or uncoated stock, or perhaps a heavier stock, you can make these changes without incurring additional expense.
If your job will be printed on an offset press, your proof will probably not be produced on the same stock as the final job. Commercial printers usually have only a limited selection of paper stocks for their inkjet proofing devices. Often you can request a coated or uncoated sheet, but the proof may not be provided on a paper that will be as thick as the stock used for the actual press run. Don’t worry. Just bring it to your custom printing supplier’s attention, and he will explain whether it is a mistake or just an example of the limits of the proofing device.
How to Check a Proof
- Check for complete copy. Match the proof to your final laser copy to make sure nothing has been inadvertently lost.
- Check the photos. Make sure they are neither too light nor too dark. Check their cropping. Check their color accuracy.
- Check the margins, page numbers, and running headers and footers. Is everything placed on the page as you had intended? Do images bleed as intended? Are the pages in the proper order?
- Check any solid colors or screens. Should the type be in color? Is the color accurate? Compare the color to your PMS swatch book. Keep in mind that a digital proofing device will print spot colors as 4-color process builds. Therefore, the color may differ from a PMS ink mixed for an offset press run. If there are problems with color on a digital xerographic proof used for an Indigo press, that’s important to note, since your proof is exactly what your final job will be (and since both the proof and the final job are usually produced with only cyan, magenta, yellow, and black inks rather than PMS colors).
Usually your proof will flawlessly match your last PDF of the job. (In fact, it’s wise to send a PDF of the job to your custom printing vendor along with the native InDesign file. This way your commercial printer will know exactly how you want the final job to look.) However, if there are any glitches introduced inadvertently by the printer’s equipment—or if there are any emergency edits—now is the time to make corrections.
If you have sent your commercial printer a high-res PDF of the job instead of a native InDesign file, it would be extremely rare for this file not to print exactly as expected. Occasionally, however, things do happen—hiccups during the RIPing process (the conversion of PostScript code into into a grid of printer dots imaged on the proof or the printing plates). Don’t assume anything. Check everything carefully. Once you have signed off on the proof, any errors you missed are your responsibility, not your custom printing supplier‘s. If you waive the option of a proof altogether, any error is your responsibility.
Uploading Corrections
If you catch errors, make corrections in your native file. Save the file under a different name (“File v1,” “File v2,” and so forth, to indicate different versions). Or, use another naming convention as long as it is clear that you are submitting a new file.
Ask for a complete second proof (not just selected pages). Probably a PDF will suffice. After all, you will have seen the photos, solids, and area screens on the first proof. However, if your corrections involve photos (particularly color photos), you will probably want a hard-copy proof of these individual pages. But still ask for a complete PDF proof as well. Why? Just to ensure that no other errors have crept into the process. If you get a PDF of the entire job for the second proof, you can be sure that all pages are in place and accurate in the second proof as well as the first. You never know. It’s better to be safe.
This entry was posted
on Saturday, December 31st, 2011 at 7:26 pm and is filed under InDesign Software, Offset Printing, Prepress, Printing, Proofing.
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