Operation Manual

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 filters, the Moire and Radius
parameters are specifically used to correct aliasing in an image caused by edges with
high color contrast. Weak anti-aliasing filters tend to curve edges, skewing the colors in
the process. During the RAW decoding process, the Mac OS scans for high-frequency
information in the RAW file, 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 first reprocess the image using Aperture 3 image processing. For
more information, see Reprocessing Images from Previous Versions of Aperture.
465Chapter 16 An Overview of Image Adjustments