UPDIG Guidelines, Version 3.0

Guide Prints and Proofs

Cross-rendered guide prints can serve as a valuable reference point for digital files, especially if the recipient is unknown or the output profile is generic. Profiling a desktop printer is critical for photographers who include digital guide prints with their digital files — a key part of these guidelines. This is particularly true with CMYK files submitted to an offset printer. Unless using a SWOP-certified proofing system, photographers should include disclaimers stating that guide prints are for color reference only and are not “contract” proofs.

Since inkjet prints made from RGB editing spaces may have wider color gamuts than available from an offset press, a guide print will more accurately reflect what is possible to achieve on an offset press if it is “cross rendered.” Cross-rendering involves printing from your current output color space through an intermediate output color space to simulate the appearance of the final output space. For example, in the print dialogue, the “source” space would be either the CMYK file or the CMYK proof space. Choosing Relative Colorimetric as the rendering intent will limit a desktop printer’s color gamut to the gamut of the CMYK file. If you use Absolute Colorimetric (or check the “simulate paper color” box in Photoshop CS2), you may more closely simulate the actual press sheet, since the whites will more closely match the duller white of the actual press stock.

Photoshop’s settings for cross-rendering a print can be found in the Print With Preview dialog. Note that Photoshop CS1 does not have the “simulate paper color” checkbox.

The Photoshop CS2 'Print with Preview' dialog, with highlighting to show the controls used in cross-rendering.

A guide print should not be confused with, or referred to, as a “proof.” That term refers to a “random” or a “contract” proof, provided by an offset printer or prepress house, and created from the actual films or plates used for press output. Direct-to-plate workflows create proofs with special printers, calibrated RIPs and special proofing media to closely simulate the actual press conditions. “Contract proofs” are considered guarantees by printers (or prepress houses) that press sheets will match the proofs.

A SWOP-certified proof provides additional precision when indicating the color of digital files delivered to an offset printer. SWOP-certified systems combine RIP software driving special proof printers. More information on SWOP-certified systems is available.