Proofing for Flexo and Packaging with Multi-color Profiles
By Ron Ellis

    Inkjet proofing has become the standard method of providing proofs in offset and other markets. However, inkjet has seen much lower adoption in the flexo market. Part of the reason for this is the flexo market’s reliance on spot colors blends rather than traditional CMYK separations. Traditional dot proofing methods and color recipes are still commonly used in flexo to accommodate custom colors and substrates. Dot proofing has practically been abandoned in the offset world, but it is because of this multi-color requirement that inkjet proofing in flexo is less prevalent than in other print methods.

    Many inkjet proofing configurations in flexo are simply CMYK proofing systems that printers have adapted to work with wide gamut color spaces. Because the color space of an Epson, for example, is often close to or large enough to the gamut a plant may be using, a printer will sometimes use a wide-gamut CMYK profile. In this scenario, the printer is using the proofing RIP’s CMYK capabilities along with the RIPs spot color libraries. Using a CMYK profile and a RIP’s spot color library rather than a multi-color profile may be adequate, but there are compromises to using this method, particularly in that it does not accurately predict the overprints of the spot colors.

    The simulation of these overprints and spot blends is a major challenge. There is a method that offers the promise of better color fidelity while still maintaining a true multi–channel workflow. This method is based on using a multi-color ICC profile as well as a proofing system that supports multi-color profiles. Multi-color ICC proofing requires a multi-color ICC profile, as well as a proofing system that supports the multi-color ICC profile. Though it sounds straightforward, multi-color ICC proofing is not as simple as using a proofing system that supports spot colors. While many proofing systems support spot colors, and even the gradation of the spot colors, only a few proofing systems fully support multi-color profiles.

    A multi-color ICC profile is an ICC profile that characterizes a number of spot colors. This multi-color ICC profile not only contains the data characterizing the solids but also contains the overprints, mixes and tints of all the included colors. The multi-color ICC profile most familiar to many people is Pantone’s Hexachrome. This system is made up of cyan, magenta, yellow, black, orange and green. Many proofing systems support Hexachrome, but fewer support other combinations. A proofing system that fully supports multi-color should be able to support seven-color profiles, 10-color profiles, or other combinations of colors. A multi-color profile often contains colors that are ordered in the same sequence as the press, and may not even contain any traditional CMYK colors.

    When configured correctly a multi-color ICC proofing system can provide a much more accurate proof than other methods. By capturing the blends and mixtures of the spot colors used in the printing process, the proof can replicate color more accurately than traditional proofing methods. In addition, new inkjet proofers have a greater color gamut and are better suited to multi-color proofing than they have ever been in the past. A multi-color ICC profile can even be used with a plug-in to create optimized separations and in applications such as Adobe Photoshop CS4 and other applications that support multi-color ICC profiles.

    Although the results can be spectacular, multi-color profiling and proofing can be a difficult, complex process. Many vendors mistake Hexachrome support as being the same a multi-color ICC support. This is fine if you are using the six Hexachome colors (CMYKOG). However, many customers use five, seven, eight or even 10 colors on press, requiring that their proofing system use those same five, seven, eight, or 10-color multi-color profiles. Because of this, support for multi-color profiles in your proofing system becomes a critical issue.

    There are many proofing systems that do not support multi-color profiles, or only partially support them. Also, because there is typically little expertise with multi-color profiling, tech support staff are often at a loss to answer questions related to multi-color configurations. Unless everything is just right between the proofing system, the multi-color ICC profile, and incoming files, the system will fail. This means if customers are changing colors at the last minute, or the files are not prepared with exact separation names matching those in the multi-color profile, the system will fail. I have had my best luck using tried and true combinations of software that give predictable and reliable results.

    â€œWe have seen a clear shift in fundamental print practices across the printing industries,” said Marc Levine, director of business development, Color Management Group. “With G7-based specifications such as SWOP and GRACoL, solid density targets have been replaced with solid colorimetry targets. By mastering the process of hitting solid color on press, it opens the door for printers to go beyond their CMYK gamut by using extended color process inks. With this effort, printers also need to ensure that their proofing systems are up to the challenge.”

    Multi-color ICC profiling is not for everyone. If you are printing with spot colors and would like an accurate prediction of overprints, blends and tints, then it is worth taking a look at. Though complex, once the system is installed and your own custom procedures are established the results can be rewarding and save you time and money.

    



 Ron Ellis is a Boston-based consultant specializing in color management, worflow integration, and press calibration. He has provided installation and training services to dealers, manufacturers, and content creators since 1986. An IDEAlliance G7 Expert and chair of the GRACoL Committee, Ron has performed over 100 G7 calibrations. In addition to calibrating pressrooms for customers such as Pantone, Ron also specializes in creating internal working spaces for brands and agencies that allow them to work more efficiently with vendors, saving both time and money. Ron is published frequently in industry magazines, and has produced training materials for numerous printing industry vendors and publishers. He can be contacted at 603-498-4553 or through his web site at www.ronellisconsulting.com.



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