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Taking Control with Color Management

(May 2006) posted on Tue May 23, 2006

This article examines the benefits of color management and uses an actual job to demonstrate how color can be controlled.

By Rick Auterson

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A common input profile allows prepress to have a standard set of builds. Pratt used to run two 300-dpi Arizona inkjet printers side by side. The printers' serial numbers were within five digits of each other, yet the same builds produced very different colors on those devices. Files were built to run on Arizona #1 or Arizona #2. If a job was moved or a press broke down, then those files went back to prepress to be reworked. These days, prepress operators build files using a standard MatchPrint input profile, and the builds are changed in the workflow to accommodate each output device.

Color-managed workflows use an input profile to convert a build into L*a*b* color space and then convert that L*a*b* image back into a build using an output profile (Figure 1). Color management makes one device simulate another. So how is that useful? A company's first steps into color management usually take the form of profiling a printing press and using that profile to simulate the press on their digital proofer. Those printers end up with a menu of proofs that simulate each device. Their files have not been truly color-managed and therefore have not benefited from controlled UCR and GCR. They are not managing color so much as predicting it. Compensation curves are still driving the workflow.

Pratt treats every device like a proofer. When a company decides to do this, then every file must be color-managed. UCR is set according to prescribed limits, and GCR is liberally applied.

Building a color-managed workflow

Pratt uses the following tools to construct and maintain its color-managed workflow: GretagMacbeth's ProfileMaker 5 software for creating and editing color profiles, SpectroScan T spectrophotometer, iQueue software for color-management workflows, and a program we developed in house to monitor and control color.

The following steps are the foundation to building a color-managed workflow in which every device produces matching images. First, select a standard for proofing, and either create an input profile or select one. Next, profile each device on each substrate, and create workflows with the standard proof as the input and the intended device as the output. Routinely check the accuracy of the workflow. Finally, take appropriate action to keep the workflow accurate, and seek continual improvement. The sections that follow explain each of these steps in more detail.


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