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Proof of what?

Oct 1, 1996 12:00 AM


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The topic of proofing isn't new. Unlike many other issues of the day, proofing challenges didn't grow out of the digital design and prepress revolution. Proofing has been an issue in the graphic arts industry for decades. Nonetheless, the introduction of digital production techniques, along with some new technologies, has brought unique problems and solutions to proofing operations.

In the professional graphic arts, proofing serves two basic functions: it allows service providers to confirm, with a certain degree of satisfaction, that what ultimately will be delivered is what the client expects. It also has been used as a sort of "insurance" plan-in case something goes wrong in the process, the proof can be a basis for further negotiations. But if the proof is approved and no problems are encountered in production, then all parties involved have incurred an expense that has no real value in the long term.

If there was a way to guarantee that a digital file would process as expected, there wouldn't be a need for proofing. Unfortunately, there are many variables in the processes of design, prepress and printing, any of which have the potential to change the outcome of the final product.

The good news is that many of those variables can be identified and controlled. As a matter of fact, mastery of some of those variables is what allowed our industry to move from press proofs to what are now called analog proofs (i.e., Cromalins, Matchprints, etc.) back in the 1970s. Standardization of process inks and, subsequently, the creation of the SWOP (Specifications for Web Offset Publications) committee-along with the publication and implementation of its recommendations-have enabled the industry to use analog proofing methods to successfully simulate the outcome of the print process. The benefits have included significantly reduced costs and cycle time.

That's not to say that a comparison of an analog proof to the final printed piece wouldn't uncover some accuracy problems. But over time, users have learned to "understand," or interpret, what can be expected on press based on the analog proof. In actuality, even with press proofs, there can be differences in the final run due to the presses used, setup, operator skill, etc.

The real issue in acceptance of a proofing technology probably has more to do with the market's willingness to learn how to evaluate a proof (relative to the final printed piece), than it does to technological limitations.

For example, when Cromalin was introduced, the industry reacted with skepticism-at best. The group that most needed convincing proved to be agency and design customers. Du Pont, which developed Cromalin, in response instituted a full-blown marketing campaign aimed at the design and advertising community. Its goals were to educate potential users and assuage any fears the creative community had about using this new technology.

At the same time this was going on, printers were being sold on the reliability of the new technology. Once print buyers started to ask for this new proof, its success was almost guaranteed.

The introduction of digital proofing into the mainstream has a lot of similarities to Cromalin. This time around, however, the move comes when our industry still is trying to define responsibilities for various operations and stages of production-a problem that didn't exist back in the 1970s. Cromalin was targeted at the prepress area, while digital proofing has the potential to be used in many steps of the whole production process, from design to pressroom.

There are many different proofing applications and at least as many proofing tools available. For example, editors need to proof what they are writing for content and "fit" on the page. Color generally isn't a factor for this proofing requirement, but the way the font looks and the copy fits is important. While this type of proofing usually is relegated to a black-and-white laser proof, the file also might be reviewed on screen, as a so-called "soft proof." Of course, this assumes the proper machine configurations are maintained. As users get more comfortable with their ability to work with a good representation of final output on computer screens, they tend to skip the "hard copy" proofing step.

Color page proofing adds a number of additional requirements beyond those required by editors. While the accuracy of the copy and "fit" on the page still are important, predictability of the color and how the colors will work together when printed take center stage.

Moving down the production chain, from design into prepress, adds requirements for details such as trapping. Further down the production line, the print shop requires proofing of back-to-front page alignment and bindery considerations, such as folding, creep, etc.

Color digital proofing has been around for a while in many different forms. The black-and-white laser printer has been around since the early 1980s, and color thermal printing dates to the late '80s. These tools were adopted by the design community as viable proofing techniques. Many print creators even started making color decisions, to the chagrin of many printers, based on melted wax on paper. While these tools may have sufficed for some design applications, they couldn't address many of the issues in the prepress and printing stages of the process.

The first viable digital color proof to answer some of the prepress proofing requirements was the Iris ink-jet proofer, which was introduced in the fate '80s. Even though it could be used to judge color press results fairly accurately (with the appropriate calibration), it was introduced to a largely skeptical marketplace. Potential users already were trying to come to grips with the digital revolution, in which equipment costs were rising and margins were shrinking. The ink-jet proofer's introduction also wasn't as well planned as that of Cromalin.

In time, better Iris and other ink-jet proofers came to market. Many dye-sublimation color proofers also were introduced. These product introductions, coupled with some shifts in process responsibility from the prepress operation upstream to the designer, fostered a wider market acceptance of color digital proofing as a viable production tool. Still, a comparison of any of these proofs to the final printed product will show clear differences.

Some of the differences may be more subtle than others, but these proofs-as is true of most proofs-require a certain degree of interpretation. That doesn't make them less valuable as production tools, especially since they offer lower cost proofing, increased ease of use and quicker turnaround. If anything, such solutions may be more valuable, given that the true value of proofing is based on catching mistakes before going on press. As long as it's reliable, any tool that encourages print creators to do more thorough proofing earlier in the process definitely is a positive.

An added benefit of digital proofing in reducing cycle time is the ability to do "remote proofing." There have been a number of attempts in the past decade to develop reliable solutions that enable a prepress operation to send a proof to its client over the phone lines. The elimination of the 12-hour (minimum) "black hole" of overnight carriers can be a welcome option for "rush" jobs.

While telecommunication speeds impact the viability of remote proofing, the file transfer step has become less of an issue with the growth in ISDN and other telecommunication technologies, coupled with developments in file compression technology. Of course, there's still the dilemma of how to ensure that what clients view coming off their digital proofers matches what press operators see in the printing plant.

There have been a number of solutions offered to address that problem. The latest of which is the "ColorLock" system that works with Imation Rainbow proofers. This system is said to offer visual assurance that proofs will match. This "proprietary" system is a valiant attempt to address color consistency, but a broader-based solution ultimately is necessary for remote proofing to really take off.

Developments in color management systems that support ColorSync, a standard system-level color management technology for the Mac, likely will lead to a final resolution of this problem. ColorSync provides the ability to "profile" proofing devices to establish their individual characteristics and compensate for variances. This will allow users to communicate a file to different proofing devices with some degree of assurance that the output can be used to judge the acceptability of the final printed piece. Of course, a certain level of interpretation still will be required.

If the goal is quicker and lower cost proofing methods, why isn't "soft proofing" of color pages the norm? After all, other than completely eliminating proofing, it is the quickest and lowest-cost solution. There are, in fact, an increasing number of companies doing just that. Tools have been introduced that improve the match between what's seen on-screen and what appears in print, but acceptance takes time.

Eliminating "hidden" process-related issues (which result from limitations in PostScript or other applications) through preflight checking has gone a long way toward ensuring the "reliability" of a file to be processed. This leaves color predictability as one of the only remaining issues, and it should be taken care of by the aforementioned developments in color management solutions.

There also are less obvious issues that need to be addressed to enable a complete transition to digital proofing. Press and bindery requirements traditionally have called for "two sided" proofs to check back-to-front page alignment. While this capability still would be nice, it really isn't necessary given the way page alignment is determined in an electronic file. The move to electronic imposition all but assures that, if properly configured, layouts will be very accurate and repeatable. Imposition software also addresses the setup requirements of bindery operations, since job parameters can be added to the layout in the imposition programs.

The two biggest unresolved proofing issues are the abilities to see overprinting and moire patterns. Overprinting has been addressed in some of the proofing systems available and should become a non-issue as the "new" PDF (Acrobat) file format, with its transparency capabilities, replaces PostScript as the de facto standard for page production.

That leaves the ability to see moire patterns as one of the only remaining "technical" challenges. While frequency modulated screening technology (stochastic) could eliminate this as an issue, it's adoption hasn't been as widespread as initially hoped. Standard dot configurations continue to be the solution of choice.

There have been some solutions suggested to the problem of seeing the "dot effect" in a digital proof, including integrating halftone dot generation for proofs with that for outputting film or plates. This would ensure a match between proof and final output, but in the greater scheme of things it isn't a practical approach. As business moves toward on-demand digital production and distribution of information, our industry will need to develop workflows and production techniques that are independent of the final output device.

That last point is kind of ironic. The capability to produce final "printed" pieces electronically actually is part of what's driving the need for digital proofing. And, the acceptance of digital printing seems to be growing faster than widespread adoption of digital proofing.

Still, where possible, today's proofing problems are being addressed by developments in technology. These developments ultimately will reduce print production costs and cycle time. They also may give users a new level of confidence that what they see in the proof will be what they get in the final printed piece.

The introduction of any new proofing solution always will be met with some skepticism, but demonstrable benefits are apt to win out in the long run. This will be the case until the ultimate solution is developed in the future, one encompassing processes and systems that automate page production and eliminate the requirement for proofing of any kind.

Dave Zwang Contributing editor and consultant specializing in the application of electronic technology in the graphic arts, based in Danbury, CT