Adobe AFTER EFFECTS CS3 PROFESSIONAL User Manual page 139

Renders one-ninth of the pixels contained in the full-resolution image.
Third
Renders one-sixteenth of the pixels contained in the full-resolution image.
Quarter
Renders the image at the resolution you specify.
Custom
Viewing a color channel or alpha channel
You can view red, green, blue, and alpha channels—together or separately—in a Footage, Layer, or Composition
panel by clicking the Show Channel button
view a single color channel, the image appears as a grayscale image, with the color value of each pixel mapped to a
scale from black (0 value for the color) to white (maximum value for the color).
To see color values displayed in the channel's own color instead of white, choose Colorize from the Show Channel
menu.
When you preview the alpha channel, the image appears as a grayscale image, with the transparency value of each
pixel mapped to a scale from black (completely transparent) to white (completely opaque).
Note: When you choose RGB Straight, which shows straight RGB values before they are matted (premultiplied) with the
alpha channel, pixels with complete transparency are undefined and therefore may contain unexpected colors.
All channels, colorized color channels, and alpha channel
You can view other channel values, such as saturation and hue, by applying the Channel Combiner effect and
choosing Lightness from the To menu.
See also
"About alpha channels and mattes" on page 252
"About straight and premultiplied channels" on page 253
"Shortcuts for using and modifying views" on page 637
"Channel Combiner effect" on page 382
Adjust exposure for previews
You can adjust the exposure (in f-stop units) for previews with the Adjust Exposure control, which is located to the
right of the Reset Exposure button
its own Adjust Exposure setting.
When the Adjust Exposure control is set to a value other than zero, the center of the Reset Exposure button is orange
The Adjust Exposure control doesn't affect final output, only how video appears during previews. To make tonal
adjustments to a layer that appear in final output, use the Exposure effect.
at the bottom of the panel and choosing from the menu. When you
at the bottom of a Composition, Layer, or Footage panel. Each viewer can have
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User Guide
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