Use 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, OS X 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.
Adjust moire reduction during RAW decoding
Select a RAW photo.
Note: If the RAW Fine Tuning controls don’t 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 the most current RAW image processing. For more information, see Reprocess photos from earlier versions of Aperture.
Adjust the amount of signal to apply the Moire adjustment to using the Moire slider and value slider.
A value of 0.00 applies no moire correction during the RAW decoding process. A value greater than 0.00 applies moire correction during the RAW decoding process.
Adjust the pixel area (visual threshold) the Moire adjustment is applied to using the Radius slider and value slider.
If supported by the camera, reduce digital noise in the image using the De-noise slider and value slider.
A value greater than 0.00 reduces noise in the image.