3.3

Chapter 17 Making Image Adjustments 349
You can also have Aperture automatically identify tonal ranges in an image using the Black Point,
Gray Point, and White Point eyedropper tools in the Curves adjustment controls. When you select
a tonal range using one of the eyedropper tools, Aperture plots the corresponding curve over
the Curves histogram.
You can also brush the Curves adjustment on selected parts of an image. For more information,
see An Overview of Brushed Adjustments on page 388.
Important: The Curves adjustment controls are only available for images using Aperture 3
image processing. For more information about reprocessing your images, see An Overview of
Reprocessing Photos on page 72.
Curves Adjustment Controls
Before applying a Curves adjustment, it’s a good idea to get acquainted with the Curves
adjustment controls.
Add Point button
Channel pop-up menu
Auto Curves
Combined button
Auto Curves
Separate button
Black Point, Gray Point,
and White Point
eyedropper buttons
Range pop-up menu
In and Out fields
•
Channel pop-up menu: Choose a color channel to apply a tonal curve to from this pop-up
menu. You can also apply the tonal curve to all color channels combined, as well as show
separate color channel overlays when tonal curve adjustments are applied to individual
color channels.
•
Auto Curves Combined button: Click this button to apply a tonal curve adjustment when
you want to correct contrast based on total luminance, without aecting the color cast of
the image.
•
Auto Curves Separate button: Click this button to apply a tonal curve adjustment when you
want to correct contrast as well as remove color casts in the image.
•
Black Point eyedropper tool: Use this eyedropper to set the black point in the image.
•
Gray Point eyedropper tool: Use this eyedropper to set the gray point in the image.
•
White Point eyedropper tool: Use this eyedropper to set the white point in the image.
•
Add Point button: Click this button to use the Loupe to sample pixels in the image and then
add a point to the tonal curve for each color channel as well as the RGB tonal curve.
•
In and Out elds: Enter the In and Out point values for a selected point on the tonal curve. The
In point represents the horizontal axis (x-axis), and the Out point represents the vertical axis
(y-axis).