Use the Boost controls
OS X characterizes each digital camera’s RAW file format to determine an optimal contrast setting. The Boost controls allow you to set the strength of the contrast when the RAW file is decoded. The Hue Boost controls are used to maintain the hues in the image as the contrast is increased using the Boost controls. When the Hue Boost parameter is set to 1.00 and the Boost parameter is set to 1.00, the hues of the primary and secondary colors are pinned to their pure color values, resulting in a shift of all the hues in the image.
For images that consist of saturated primary and secondary colors, such as an image of flowers in a lush garden, shifting the hues to their true values has a desirable visual effect. However, this is not visually desirable for images containing skin tones. Shifting the hues most often causes the skin to appear yellow. Setting the Hue Boost parameter to 0.00 increases the color contrast in the image while preserving the original hues in the image.
Adjust contrast applied 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.
In the Adjustments inspector or the Adjustments pane of the Inspector HUD, adjust the Boost parameter using the Boost slider and value slider.
A value of 0.00 applies no contrast adjustment to the image during the RAW decoding process. A value greater than 0.00 increases the contrast adjustment. A value of 1.00 applies the full Apple-recommended contrast adjustment for the specific camera model.
Adjust the Hue Boost parameter using the Hue Boost slider and value slider.
A value of 0.00 preserves the original hues in the image in relation to the Boost adjustment (color contrast) during the RAW decoding process. A value greater than 0.00 increases the hue adjustment. A value of 1.00 applies the full Apple-recommended hue adjustment for the specific camera model.