Apple Aperture - Manual (Page 154)

154 Part II Photo Editing
Choosing a Color Value Sample Size
You can also set the sample size (pixel area) Aperture uses to determine color values.
To choose a color value sample size for the Color meter:
m In the Adjustments Inspector or Adjustments HUD, choose an appropriate color value
sample size from the Adjustment Action pop-up menu.
Showing Hot Areas in Your Images
Images may occasionally have areas that can’t be reproduced by a printer. For example,
white areas in an image brightly lit with direct sunlight, or bright flashes off a water
surface, may be so bright that their color is outside the color gamut of a printer. You may
be able to adjust these areas by changing the exposure or the gamma setting of the
image. Aperture can display these “hot areas” of an image with red tints on the image.
To show the hot areas in your images:
m Choose View > Highlight Hot Areas (or press Shift-Option-H).
Choose a color value sample size here.