Operation Manual

Using the Boost Controls
The Mac OS 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.
To adjust the Boost 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.
2 In the Adjustments inspector or the Adjustments pane of the Inspector HUD, adjust the
Boost parameter by doing one of the following:
• By default, the Boost slider is set to 1.00. Drag the Boost slider to the left to decrease
the amount of contrast applied to the image during the RAW decoding process, and
drag the Boost slider back to the right to increase the contrast.
• Click the left or right arrow in the Boost value slider to adjust the contrast by 5 percent
increments, or drag in the value field.
• Double-click the number in the Boost value slider, then enter a value from 0.00 to 1.00
and press Return.
Use the Boost slider and value
slider to adjust the amount of
contrast applied during the RAW
decoding process.
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 to the image. A value
of 1.00 applies the full Apple-recommended contrast adjustment for the specific camera
model.
3 Adjust the Hue Boost parameter by doing one of the following:
• By default, the Hue Boost slider is set to 1.00. Drag the Hue Boost slider to the left to
preserve the accuracy of the hues, and drag the Hue Boost slider back to the right to
allow the hues to shift during the RAW decoding process.
462 Chapter 16 An Overview of Image Adjustments