Apple Aperture 3.5 - Manual (Page 302)

Chapter 7 Make image adjustments 302
You adjust the levels of the blue color channel when you want to remove blue and yellow color
casts in the image.
Before Blue Levels adjustment After Blue Levels adjustment
(moved White Levels and Gray Levels sliders left)
1 If the Levels controls aren’t shown in the Adjustments inspector or the Adjustments pane of the
Inspector HUD, choose Levels from the Add Adjustment pop-up menu.
2 To adjust the levels of the red color channel, choose Red from the Channel pop-up menu, and do
any of the following:
Choose a color channel from
the Channel pop-up menu.
White
Levels slider
Black Levels slider Grey Levels slider
•
To add cyan to the shadows, removing red: Drag the Black Levels slider to the right.
•
To add red to the midtones, removing cyan: Drag the Gray Levels slider to the left.
•
To add cyan to the midtones, removing red: Drag the Gray Levels slider to the right.
•
To add red to the highlights, removing cyan: Drag the White Levels slider to the left.
3 To adjust the levels of the green color channel, choose Green from the Channel pop-up menu,
and do any of the following:
•
To add magenta to the shadows, removing green: Drag the Black Levels slider to the right.
•
To add green to the midtones, removing magenta: Drag the Gray Levels slider to the left.
•
To add magenta to the midtones, removing green: Drag the Gray Levels slider to the right.
•
To add green to the highlights, removing magenta: Drag the White Levels slider to the left.
4 To adjust the levels of the blue color channel, choose Blue from the Channel pop-up menu, and
do any of the following:
•
To add yellow to the shadows, removing blue: Drag the Black Levels slider to the right.
•
To add blue to the midtones, removing yellow: Drag the Gray Levels slider to the left.
•
To add yellow to the midtones, removing blue: Drag the Gray Levels slider to the right.
•
To add blue to the highlights, removing yellow: Drag the White Levels slider to the left.
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