Show Metallics, Varnishes

  Without knowing who will print the job, it is possible for creatives to reap the benefits of color management, thanks to standards-based ICC output profiles.
Improvements in inkjet reproduction were never brought into sharper focus than during this year's Proofing RoundUP study from the IPA. Lead by Abhay Sharma, PhD, of Ryerson University's School of Graphic Communications in Toronto, the RoundUP offered an examination of 27 digital color proofing systems, including inkjet printers as well as several halftone-dot proofing systems. Evaluations of these proofs were completed during IPA's 2005 Technical Conference in Chicago; a final report summarizing the study was recently released for purchase (www.ipa.org). It includes the results of all testing procedures, as well as a detailed comparison of system features including price, speed and cost per proof.

  The IPA Proofing RoundUP study subjected each system to a comprehensive battery of tests, including a subjective (visual) analysis of each proof's resemblance to a printed test form run on an offset press, and an objective (colorimetrically measured) analysis of each proof's accuracy in reproducing an ECI2002 color management target. Also included were subjective and objective analysis of spot color reproduction accuracy, featuring a target built from 11 spot colors in both solid and tinted patches as well as an image printed with four non-CMYK colors. Testing was performed to verify PDF/X-3 compliance of each proofing device's raster image processor, based on the Visual and Technical pages of the Altona Test Suite.

  The printed form used for IPA's test was run to the GRACoL standard (General Requirements for Applications in Commercial Offset Lithography), the emerging North American standard for commercial offset lithography, soon to issue its seventh udpate. With higher ink densities and lower dot gain than the venerable SWOP standard, this new method of quantifying reproduction expectations will undoubtedly have a major impact on the high-quality sheetfed printing marketplace.

  European companies will tell you that a lot of U.S. printers don't really follow the SWOP standard...

  A virtual surprise for inkjet

  One of the big surprises to emerge in the IPA Proofing RoundUP was that the six systems showing the greatest average color accuracy (when objectively compared for colorimetric accuracy in rendering the ECI2002 target), were all inkjet devices. Of perhaps greater importance was the finding that none of the inkjet proofs varied from the target by more than two deltaE, offering a near perfect visual match for most observers. "There is little room for further improvement as the results are at the limit of instrument repeatability, inkjet and press stability, and the deltaE numbers at the limit of human vision discernability," Dr. Sharma notes in IPA's recently released Special Report summarizing the RoundUP results.

  But just as inkjet vendors might be expected to enjoy a collective toast over this new-found technical prowess, a new gunslinger arrived to challenge the popular champion. When the Proofing RoundUP study asked a dozen experienced color experts to subjectively evaluate visual matches between proofs and a press sheet, the top five results were dominated by four virtual on-screen proofing systems. Based on calibrated computer displays, this new breed of proof already threatens to disrupt the recently established dominance of inkjet devices.

  Nearly all of the top-rated "soft proofs" were driven by Kodak's Matchprint Virtual Proofing System (the one exception being Creo's Synapse InSite, now a product of Kodak, which took fifth place). In what almost qualified as a soft-proofing shootout, the most interesting revelation was that all these top-ranking systems were based on LCD flat-panel monitors from either Apple or EIZO (as opposed to traditional cathode-ray tube monitors).

  Densitometry and colorimetry now are available on press. KBA's Densitronic system measures color densities in control strips and compares spectral/colorimetric values within images on a two-up sheet. Soft proofs in action

  Soft proofing is working quite well at a leading international advertising agency. Chicago-based Leo Burnett strives to implement workflows that can work internationally as well as in the U.S. Joe Duncan, Burnett's VP director of print innovation & technology, says the immediacy of Kodak's Matchprint Virtual Proofing System allows projects to span continents.

  "Cultural differences, how we communicate color - it used to be a hard thing to match color sent to Europe for print production," says Duncan. "Matchprint Virtual has allowed us to have a common starting point and a standardized reference for how color needs to appear through various stages of the process. We use the system to coordinate the desired color, and they adapt our profile to their print conditions to achieve a match."

  Duncan also believes that a calibrated computer display provides a more realistic simulation of substrate color than traditional film-based proofs. "Instead of rich saturated colors on white stock, you're doing a better job of telling them how it's actually going to look on newsprint running through a web press," Duncan says. "It's had a huge impact on our ability to preview imagery, regardless of where or how the job is destined to be printed."

  Virtual proofing workflows are an excellent choice for standards-based proofing, since these paperless proofs can be immediately shared across town or between continents-situations in which a blind hand-off of work between unfamiliar partners is the norm. This drives the need for output profiles based not on a specific printshop or the physical condition of a single printing press, but on well-defined characterizations of ideal print conditions. From our history prior to color management-when we adjusted wildly variant presses to match an only slightly more consistent proof-we've come full circle back to a workflow in which the proof is, once again, viewed as gospel.

  Brief history of proofs

  Twenty-five years ago, print operated in a wild and woolly frontier, with no generally pervasive rules or standard procedures. Process control was not a familiar concept to the average press operator. Densitometers were used inconsistently, if at all. Spectrophotometers, now seen routinely at consoles or even on press, were too expensive for nearly anyone to consider - unless, that is, they worked for one of the ink manufacturers.

  By using L*a*b* compensated plates, prepress departments can now communicate color values to pressrooms.

  Virtual proofing workflows are an excellent choice for standards-based proofing, since these paperless proofs can be immediately shared across town or between continents - situations in which a blind hand-off of work between unfamiliar partners is the norm. This drives the need for output profiles based not on a specific printshop or the physical condition of a single printing press, but on well-defined characterizations of ideal print conditions. From our history prior to color management - when we adjusted wildly variant presses to match an only slightly more consistent proof - we've come full circle back to a workflow in which the proof is, once again, viewed as gospel. Prepress departments only compounded this lack of consistent practices: images were converted to CMYK during the scanning process based on little more than operator knowledge of what had worked the day before. Color proofs were generated using analog photomechanical processes. Each of the process colors were subjected to successive exposures of UV light for the individual separated negatives, obscured by layers of rubylith and clear film stripping. Successive laydowns varied with humidity.

  The finesse of the proofer's wrist action was a key critical factor as receiver and donor sheets were pulled apart with a prayer that the proof would succeed.

  Suffering under the enormous number of variables present in this film-based prepress workflow, press operators and their clients both longed for something - anything - that could represent a consistent, achievable result. So, despite its inherent inconsistencies, the contract proof was elevated to that role. It became the target for the press operator to emulate.

  Generating dozens of custom press profiles is an impractical workflow.

  In comparison to the wild performance variances at play in printing presses, the consistent colorants and built-in dot gain of traditional color proofs at least offered a semblance of repeatability and security. Never mind that little thought was given to the fact that the plate frame's exposure diminished unpredictably as its light bulb aged. Or that the amount of exposure itself was set by eyeballing the first solid step on a continuous tone grayscale. Or even that problems with achieving an adequate level of vacuum in the plate frame could lead to wildly changing results - the photomechanical proofing materials offered by companies such as 3M (Matchprint), Fuji (Color-Art) and DuPont (Cromalin, WaterProof) were sign posts on the frontier, guiding press operators out of the wilderness and towards a color reproduction that could garner client approval.

  The attempt to curb this lawlessness began in earnest with the 1986 release of the Specifications for Web Offset Proofing (SWOP). Though SWOP had first been published nine years earlier, the 1986 booklet was the first to include practical guidelines for press and prepress operations. By setting standardized guidelines for these previously undisciplined activities, the SWOP committee made it possible to speak in terms of "typical" press conditions.As the years passed, better instrumentation and additional research provided a more detailed profile of how ink and paper usually interact within various sectors of the printing industry. By the early 1990's, smoke signals on the horizon warned of impending change: Linotype-Hell had invented a method for transforming color from the scanner into CMYK separations based on measured spectral data rather than an operator's skill in twisting knobs. When Heidelberg acquired Linotype-Hell?s prepress business in '97, joint efforts were well underway with Apple Computer to convert this color transformation workflow into an underlying component of the graphic arts process. Apple called this effort ColorSync and initiated a working group familiar today, the International Color Consortium (ICC), to oversee its implementation.

  Like a stampede, the progress made by the ICC and its member companies has spread during the early years of this new century. Recent advances in color measurement, management and reproduction have contributed to the industry's latest generation of print reproduction standards. The numbers for dot gain, density, hue and other values specified within these standard profiles are based on careful analyses of some of our best printshops, averaged to provide a composite portrait of what a high-quality job looks like. Whether the proofing system is built on tried and true halftone dots, the new wave of high-res inkjet devices or the warm glow of virtual "soft" technology, success in the global marketplace depends on a printer's ability to hit these standard numbers.