Adobe After Effects - Manual (Page 209)

Auto
Note:
Full
Half
Third
Quarter
Custom
Note:
To the top
Note:
To the top
image. For each view, there are two such ratios—one for the horizontal dimension and one for the vertical dimension.
Each composition has its own Resolution setting, which affects the image quality of the composition when it’s rendered for previews and final
output. Rendering time and memory for each frame are roughly proportional to the number of pixels being rendered.
When you render a composition for final output, you can use the current Resolution settings for the composition or set a resolution value in the
Render Settings dialog box that overrides the composition settings. (See Render settings.)
You can choose from the following Resolution settings in the Composition Settings (Composition > Composition Settings) dialog box or from the
Resolution/Down Sample Factor menu at the bottom of the Composition panel:
(available only for previews) Adapts the resolution of the view in the Composition panel to render only the pixels necessary to preview the
composition at the current zoom level. For example, if the view is zoomed out to 25%, then the resolution automatically adapts to a value of 1/4—
shown as (Quarter)—as if you had manually chosen Quarter. If a panel contains multiple views, the resolution adapts to the view with the highest
zoom level. This setting gives the best image quality while also avoiding rendering pixels unnecessary for the current zoom level.
The Auto setting is ignored for compositions for which the Advanced composition setting Preserve Resolution When Nested is selected.
Renders each pixel in a composition. This setting gives the best image quality, but takes the longest to render.
Renders one-quarter of the pixels contained in the full-resolution image—half the columns and half the rows.
Renders one-ninth of the pixels contained in the full-resolution image.
Renders one-sixteenth of the pixels contained in the full-resolution image.
Renders the image at the horizontal and vertical resolutions that you specify.
The resolution (down-sample factor) of a Layer viewer is tied to the resolution of the Composition viewer for the composition in which the
layer is contained.
View 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
at the bottom of the panel and choosing from the menu. When you 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).
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.
You can view other channel values, such as saturation and hue, by applying the Channel Combiner effect and choosing Lightness from the To
menu.
To switch between showing the alpha channel and showing all RGB channels, Alt-click (Windows) or Option-click (Mac OS) the Show Channel
button.
Alpha Boundary and Alpha Overlay view modes are only available in the Layer panel, and they are intended for use with the Roto Brush effect.
For information on these modes, see Layer panel view options.
Adjust exposure for previews
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