Macintosh OS X includes a nifty utility called DigitalColor Meter that can help you determine how accurately your monitor is producing color. You'll find it in the Applications> Utilities folder.
To use it, first profile your monitor using Apple's Display Calibrator (System Preferences> Displays, in the Color tab) or another utility. Open Photoshop. Open DigitalColor Meter and move it near the center of your screen. Drag the Aperture Size slider to the left. From the pop-up menu in the utility's window, choose "RGB As Actual Value, 8-bit."
Start Photoshop. Open the Swatches palette and move it close to the DigitalColor Meter window. From the Swatches palette menu, choose Reset Swatches, then click OK. (If you have custom swatches in the palette, you'll want to use Edit> Preset Manager to save them before resetting the palette.)
Across the top of the Swatches palette, the first six readings should be:
Switch DigitalColor Meter to RGB as Percentage.
Measure the gray swatches in the top and second rows of the Swatches palettes. The values should be close to the appropriate gray percent, but more importantly, the amounts of each of the three component colors should be equal.
If the color and/or gray readings you see using DigitalColor Meter are not correct, you should recalibrate your monitor. (And you may find that the most accurate readings come using a "stock" profile, such as Adobe RGB, in System Preferences> Display.)
Pete
Bauer is the Help Desk Director for NAPP, as well
as a Contributing Writer for Photoshop User and Mac Design
magazines. His books include "Special Edition Using
Adobe Photoshop 7" (with Jeff Foster), "Special
Edition Using Adobe Illustrator 10," "Sams Teach
Yourself Adobe Illustrator 10 in 24 Hours" (with Mordy
Golding), and "Special Edition Using Adobe Illustrator
9." Pete writes documentation for a variety of computer
graphics related products, as well as testing software
for a number of companies. As a computer graphics efficiency
consultant, Pete specializes in customized training programs.
He is based in Columbus, Ohio, and can be contacted via
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