Co-op Color

The color management process hinges on consistency and the interoperability of print job components.

By Jessica Millward, Associate Editor

Call it the ultimate communicator. Your typical color management system (CMS) is charged with translating the appearance of color from origination source to monitor to proof. And this is no rough translation. Nuance means everything in the realm of color—the difference between sun-ripened yellow and burnt orange. The ongoing evolution of printing from art to science has initiated the systemization of color management. The challenge for CMS originators now is to keep the lines of communication open between themselves, their customers, and even their competitors.

Calibrate, characterize

The process of modern color management, for every job, encompasses a variety of equipment, software, and at least one supplier-independent standard.

It all starts, however, with device calibration. Because monitors can change drastically over time, the use of colorimeters to determine if and where performance drift has occurred is vital to color consistency. The output device, too, must therefore undergo the calibration process. Using a colorimeter, densitometer, or spectrophotometer, and corollary software, the printer or press can be adjusted to match software-specified output.

The second aspect of color management, device characterization, involves formulating custom profiles for input and output devices. The International Color Consortium (ICC) regulated this process by creating an industry-wide specification for a color profile format.

Manufacturers and printers alike emphasize the need for total consistency, throughout every step of the printing process, in maintaining a successful color-managed workflow. Cathy Hofknecht, marketing manager at GretagMacbeth, believes, "There are several 'official' press standards; however, what is really important is to simply ensure you always run the press consistently. This starts with standardizing all variables that affect the press—films, plates, inks, paper, etc."

General reference

The ICC standard is built upon the idea of the PCS (Profile Connection Space) reference media. ICC profiles therefore contain data that transforms device colors to the PCS, and from the PCS to device space.

While this system has been widely accepted throughout the printing industry, it isn't immune to criticism. The definition of the PCS is sometimes categorized as too narrow, because it does not define such aspects of the reference space as blackpoint and flare.

Here too arises the issue of interoperability. Because the ICC profile often employs look-up tables to estimate functions, the correct value may need to be approximated, and each CMS performs this process differently. Hofknecht concedes, "The final quality of ICC software depends on the vendor, since it involves sophisticated mathematical algorithms to properly characterize a device."

Tools of the trade

Though Screen USA has sold the majority of its color management technology to commercial printers, Marketing Specialist Yukiyoshi Tanaka confirms, "[LabFit and LabProof] tools are fit for any package printers who print good quality color."

Actually, both LabFit, the CMS, and LabProof, a proofing system, are bundled together under Screen's prepress and print quality management suite, P2QM. LabFit generates ICC profiles for all the fluctuating conditions in a printing environment. The LabFit Builder color-measures printed sheets in four minutes, by utilizing the company's 85-patch color control bar, while the Editor provides fine-tuning of color, and the ability to edit ICC profiles generated by other applications.

The CreoScitex Prinergy™ color management capability consists of two major processing steps for color space conversions. First, during the refining process, input data for the press is separated so the refined PDF contains the color required by the digital master for subsequent trapping and final output. Color profiles can be appended to input files or applied during refining. Second, color management directs the proofing stage, so the proof accurately simulates the final output to press.

Fringe benefits of the CreoScitex system include shortened design cycle times; full color gamut representation; remote proofing; and multiple outputs to media or printing processes.

Along with its range of specific color measurement devices, GretagMacbeth also recently launched the 3.1 version of the ProfileMaker Professional color management software, which enables accurate profiling of flat panel displays, and a new module for creating digital camera profiles.

The suite is comprised of five modules, each with an intuitive graphical user interface. ProfileMaker, the main application module, calculates ICC profiles for a large assortment of input and output devices. The ColorChecker DC color reference chart enables a broad representation of color gamut. Working with measurement devices, MeasureTool handles all data collection, analysis, and calculation. ProfileEditor controls lightness, contrast, and saturation, as well as the gradation curve. Finally, BatchMatcher provides automatic attachment of ICC profiles to files prior to output.

Agfa's ColorTune and ColorTune Pro are stand-alone software packages designed to work with any prepress software. ColorTune deals exclusively with the input profiles, while ColorTune Pro allows the user to develop both input and output device profiles. The product comes inclusive of an extensive library of generic profiles, as well as the ability to work with multiple file formats.

How useful will this technology be to the package printer? While many small and mid-size printers may not yet be rushing to tackle the complicated processes involved in a CMS, suppliers expect the move to all-things-digital will continue to keep a steady pace, and will carry with it a gradual acceptance of color management. GretagMacbeth's Hofknecht predicts, "As digital proofing becomes more widespread, color management will allow printers to extend digital workflows into the prepress process."