Using the moire controls – Apple Aperture 2 User Manual
Page 355
Chapter 14
An Overview of Image Adjustments
355
III
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 to monochromatic images. The Moire adjustment controls 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 high-color-
contrast edges. 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. For more information, see “