Mastering the technique: Gray Component Replacement

Folio: The Magazine for Magazine Management, Sept, 1989 by Alex Brown

Mastering the technique: Gray Component Replacement

Production managers have the demanding duty of coordinating a host of suppliers, and they quickly learn that they must understand each vendor's specialty well enough to ask the right questions and give a few answers of their own. Nowhere is this need for technical knowledge greater than in utilizing the Gray Component Replacement technique in color separations. Gray Component Replacement (GCR) is a relatively recent approach, and work here is further complicated by the lack of application standards. This article will acquaint you with the technical basis for GCR and offer some guidelines for applying the technique to your color reproduction. You'll find that your mastery of the concept is vital to integrating your suppliers' contributions.

GCR and color reproduction.

Get a few production people together and you'll hear GCR called everything from a brilliant breakthrough to smoke and mirrors. The former opinion takes note of the clear value of the principle, and the latter reflects the wide range of results achieved without standardized specifications. Let's look at the benefits implied by the concept first.

In a separation made with the Gray Component Replacement technique, the neutral color element of each tone is made with black ink instead of a neutral mix of process colors (see sidebar for details). As a concept, GCR is clearly a wise approach to color reproduction. It should yield purer hues because the darkening is produced by a neutral black instead of a trace color. Further, since ink is a wet film applied at great speed in printing, anything we do to limit the problems inherent in trapping translucent inks will improve reproduction. In GCR, we use less black ink than the process ink we're replacing. Finally, we're building color in a theoretically more stable manner.

When we eliminate the process yellow as the gray component in a blue, all the adjustments made to yellow on the printing form overall have no effect on this hue. At an extreme, we've greatly reduced three-color overprints in every area except for the browns we're seeking froma full yellow, magenta and cyan mix. Although there are few tones in a color original that can be broken down without some use of all three process inks, we've eliminated some and reduced the trace amounts in all others. Practically speaking, we should achieve easier color adjustment on press since we'll tend to jocky black and two colors, not three, for major corrections.

Benefits in practice

If GCR earned its pie-in-the-sky reputation for any good reason, it's because early proponents of the technique promised printers greatly reduced ink consumption and lightning-fast makereadies. In practice, GCR is not quite this godsend. In large part, a GCR revolution can't take place as long as magazine publishers include ad pages produced by the chromatic method. Even if all the editorial color on a form is created with GCR, the random conventional ads will continue to demand ink consumption and color correction in makeready as they always have. However, we have learned that combining chromatic and achromatic separations poses no problem of its own.

The process color inks are more expensive than black ink, and in theory the reduction in process inks from GCR should yield real dividends to magazine printers and publishers. In fact, printers so far are not reporting any measurable savings. There are at least two likely explanations. First, GCR can be applied at any intensity, and when used cautiously it will not convert much process color to black. Second, it's been suggested that the greater color stability of GCR separations inspires pressmen to increase ink levels overall to improve the brilliance of ads and GCR subjects alike. Whatever the reason, printers are not tripping over themselves to offer you ink consumption discounts for GCR separations. In time, the benefits in ink reduction may be more apparent, but even if you're buying ink by the pound instead of the page, you may see little savings.

GCR would simplify makeready if it were not for the array of pre-press vendors represented in any given magazine signature. Between the usual inline conflicts and variations in proofs, your editorial color may fight with ad separations to keep the makeready process the same struggle it's always been. A catalog publisher is in the best position to reap the benefits of a speedy makeready because he can utilize GCR in all the separations. Magazines can't take such an all-or-nothing approach.

Nevertheless, some printers report substantial improvements in makeready time when GCR is used in editorial work alone. When all is said and done, any procedure that helps a printer reach acceptable color sooner is going to obtain support. Although some printers haven't found any particular improvement in makeready with GCR, the proponents of the technique mutter that these unconverted souls simply haven't been exposed to proper GCR. As we'll see, it's not simple to define proper GCR, and GCR zealots are to be forgiven for assuming that unimpressed printers have simply worked with unimpressive GCR.