Use of Scanners as the Image Input Devices in the Prepress Workflow

Posted on 09-01-2014 by

The part includes job functions related to images capture with an RGB scanner, and subsequent adjustment, retouching, "toning," and other image-editing tasks. Color management can be of great benefit in scanning. Characterizing the scanner will help the operator just learning to "home in" on more accurate scans right away. Color-managed scans can save the experienced operator work by producing more accurate scans with which to start the image adjustment process, it required.

To characterize a scanner, it is necessary to have IT8.7 scanner characterization targets. Because different photographic emulsions use proprietary dye sets, and because scanners "see" these dye sets differently than the human eye does, users should have reflective and transmissive targets for each brand of photographic emulsion used, e.g., Agfa, Fuji, Kodak, or other manufacturer. Each target should have an accompanying IT8.7 data reference file of target measurements that are accurate for the target bening used. "Accurate" means that the data reference file measurements agree with the color values of the IT8 target, and that the target has not faded or otherwise changed since the data reference file measurements were made. A color management program for making scanner profiles will also be necessary. To make a scanner profile:

1. Scan the IT8.7 target Crop the target so that the final image is of a file size recommended by the color measurement software publisher (e.g., 1.5~5.0MB). Save in RGB-TIFF format (or as recommended by the publisher).

2. Open the IT8.7/2 scan in the color management program, along with the IT8.7/2 data reference file, and make the profile. Apply the profile using the Apple ColorSync Plug-in filters or other ColorSync-compatible program.

There are many ways that scanner profiles can be applied: in ColorSync-compatible scanning, image-editing, page-layout, and workflow-management program. More and more scanner manufacturers are providing ColorSync compatibility in their scanning software, including Agfa, Fuji, Howtek, Linotype-Hell, Scitex, and others.

As alternatives to Adobe Photoshop, several publishers have written color scanning/bitmap image-editing programs with settings designed after those of high-end drum scanners, including tone reproduction, gray balance, and color correction. Examples include color Solutions' ColorBlind Edit, Linotype CPS's LinoColor, and Monaco Systems' Monaco-EXPERT.

Color Management Tools Used

Generally digital photographer and color scanner operator use the following color management tools.

For digital photography:
• ICC-compatible scanners (camera) characterization program with IT8.7/2 reflective scanner characterization target and IT8.7/2 data reference file;
• Professional-quality color monitor with monitor calibrator;
• Color-correction program.
For color scanner:
• RGB scanner with ICC-compatible operating software;
• ICC-compatible scanner characterization program with IT8.7 scanner characterization targets and IT8.7/2 data reference files for each brand of transparency and photo paper scanned;
• Professional-quality color monitor with monitor calibrator;
• Color-correction program;
• Output device profiles for presses/proofers (including ICC ink profiles for press simulation on digital proofers) to view simulated color output and gamut limitations.

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