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Table Of Contents
Chapter 16 An Overview of Image Adjustments 293
Using the Moire Controls
Digital images often have color artifacts that appear around edges and lines because of noise
created by digital image sensors. Images whose subjects have linear patterns often introduce
a moire pattern that gives the subject a wrinkled or rainbow-colored appearance. In addition,
cameras with image sensors employing Bayer patterns often introduce noise into monochromatic
images. The Moire adjustment controls in the RAW Fine Tuning area of the Adjustments inspector
or the Adjustments pane of the Inspector HUD identify these patterns and correct these artifacts.
Because many digital cameras have weak anti-aliasing lters, the Moire and Radius parameters
are specically used to correct aliasing in an image caused by edges with high color contrast.
Weak anti-aliasing lters tend to curve edges, skewing the colors in the process. During the RAW
decoding process, OS X scans for high-frequency information in the RAW le, looking for blended
colors, and then replaces the blended colors with the edge colors that originally existed in the
scene. The Moire parameter adjusts the amount of signal to apply the adjustment to. The Radius
parameter adjusts the pixel area (visual threshold) the adjustment is applied to.
Note: The Moire controls replace the Chroma Blur controls found in previous versions
of Aperture.
To adjust the Moire and Radius parameters
1 Select a RAW image imported with or reprocessed using Aperture 3 image processing.
Note: If the RAW Fine Tuning controls do not appear in the Adjustments inspector or the
Adjustments pane of the Inspector HUD, the selected image is from a previous version of
Aperture. You must rst reprocess the image using Aperture 3 image processing. For more
information, see An Overview of Reprocessing Photos on page 72.
2 Adjust the amount of signal to apply the Moire adjustment to by doing one of the following:
•
The default value for the Moire slider and value slider is 0.00. Drag the Moire slider to the right
to increase the amount of signal the Moire adjustment is applied to during the RAW decoding
process, and drag the Moire slider back to the left to reduce it.
•
Click the left or right arrow in the Moire value slider to adjust the intensity by 5 percent
increments, or drag in the value eld.