Apple Aperture 2 - Manual (Page 433)

Chapter 15 Making Image Adjustments 433
III
Selectively Adjusting the Brightness of an Image with the Shadow
Brightness Levels and Highlight Brightness Levels Sliders
You can selectively adjust the brightness of the shadows and highlights in the image
using the Shadow Brightness Levels and Highlight Brightness Levels sliders.
To selectively adjust the brightness of the shadows and highlights in an image:
m Drag the Shadow Brightness Levels and Highlight Brightness Levels sliders until the
brightness values of the shadows and highlights in the image are correct.
Using Levels for Color Correction
A powerful way to color correct an image is to adjust the levels of each color channel in
the image. Adjusting the levels of each color channel is useful for removing color casts
in an image. It’s important to understand that you’re adjusting the colors of the image
within the RGB spectrum; therefore, you reduce yellow when you increase blue, you
reduce magenta when you increase green, and so on.
To adjust the levels of a single color channel in an image:
1 In the Levels area of the Adjustments inspector or the Adjustments pane of the Inspector
HUD, choose a color channel from the Channel pop-up menu.
2 Drag the Black Levels, Gray Levels, and White Levels sliders (or enter values in the
corresponding fields) to create the effect you want.
For more information about making specific adjustments to the levels of each color
channel, see the next sections.
Drag the Shadow
Brightness Levels (on the
left) and Highlight
Brightness Levels sliders
to selectively adjust the
brightness of an image.
Choose a color channel
from the Channel
pop-up menu.