Keyframes are used to set parameters for motion, effects, audio, and many other properties, usually changing them over time. A keyframe marks the point in time where you specify a value for a layer property, such as spatial position, opacity, or audio volume. Values between keyframes are interpolated. When you use keyframes to create a change over time, you typically use at least two keyframes—one for the state at the beginning of the change, and one for the new state at the end of the change.
When the stopwatch is active for a specific property, After Effects automatically sets or changes a keyframe for the property at the current time whenever you change the property value. When the stopwatch is inactive for a property, the property has no keyframes. If you change the value for a layer property while the stopwatch is inactive, that value remains the same for the duration of the layer.
When the stopwatch is active for a specific property, After Effects automatically adds or changes a keyframe for the property at the current time whenever you change the property value.
To activate the stopwatch and enable keyframing, do one of the following
Click the keyframe navigator button for the layer property.
Choose Animation > Add [x] Keyframe, where [x] is the name of the property you are animating.
Click a segment of the layer property’s graph in the Graph Editor with the Pen tool .
To turn auto-keyframe mode on, choose Enable Auto-keyframe from the Timeline panel menu. When Auto-keyframe mode is enabled, modifying a property automatically activates its stopwatch and adds a keyframe at the current time.
Auto-keyframe mode doesn’t automatically activate the stopwatch for properties that aren’t interpolated, such as menus, checkboxes, and the Source Text property.
Auto-keyframe mode is off by default. When Auto-keyframe mode is off, modifying properties and animating with keyframes behave as in previous versions of After Effects.
After you set the initial keyframe for a property, After Effects displays the keyframe navigator. You can use the keyframe navigator to move from keyframe to keyframe or to set or remove keyframes. When the keyframe navigator box is filled with a diamond, the current-time indicator lies precisely at a keyframe for that layer property. When the keyframe navigator box is not filled , the current-time indicator lies between keyframes.
To detach the keyframe navigator from the A/V Features column to function as its own column, choose Column > Keys from the Timeline panel menu.
A. Keyframe at current time B. No keyframe at current time C. No keyframes for layer property
For instructions for moving the current-time indicator to other elements and times, see Move the current-time indicator (CTI).
In layer bar mode, by default, the unselected keyframes are gray and selected ones have blue outlines. You also have the option to apply different colors to these keyframes for easy identification and management. (See Keyframe Color Labels.)
In Graph Editor mode, the appearance of a keyframe icon depends on whether the keyframe is selected, unselected, or semi-selected (another keyframe in the same property is selected). Selected keyframes are solid yellow. Unselected keyframes retain the color of their corresponding graph. Semi-selected keyframes are represented by a hollow yellow box.
To toggle viewing of the free-transform bounding box in the Graph Editor, click the Show Transform Box button at the bottom of the Graph Editor.
The Select Previous/Following Keyframes commands aren’t available if more than one keyframe is selected.
When you select one or more keyframes, the keyframe menu becomes available at the bottom of the Graph Editor.
To open the keyframe menu, right-click (Windows) or Control-click (Mac OS) a keyframe.
Displays the value of the selected keyframe. If more than one keyframe is selected, the Display Value command is available, which displays the value of the highlighted keyframe in the selection.
Opens a dialog box in which you can edit the value of the keyframe.
Allows assigning of color to the selected keyframe. (See Keyframe Color Labels.)
Select Keyframe Label Group
Selects keyframes with the same color group on a selected layer or all layers.
Select Equal Keyframes
Selects all keyframes in a property that have the same value.
Select Previous Keyframes
Selects all keyframes preceding the currently selected keyframe.
Select Following Keyframes
Selects all keyframes following the currently selected keyframe.
Toggle Hold Keyframe
Holds the property value at the value of the current keyframe until the next keyframe is reached.
Opens the Keyframe Interpolation dialog box.
Rove Across Time
Toggles Rove Across Time for spatial properties.
Opens the Keyframe Velocity dialog box.
Opens a submenu with the following options:
Convert Audio To Keyframes
Analyzes amplitude within the composition work area and creates keyframes to represent the audio.
Convert Expression To Keyframes
Analyzes the current expression and creates keyframes to represent the property values it describes.
Automatically adjusts the influence into and out of a keyframe to smooth out sudden changes.
Easy Ease In
Automatically adjusts the influence into a keyframe.
Easy Ease Out
Automatically adjusts the influence out of a keyframe.
Converts the rate of change in scale from linear to exponential.
RPF Camera Import
Imports RPF camera data from third-party 3D modeling applications.
Opens the Sequence Layers assistant.
Reverses selected keyframes in time.
Assign colors to keyframes in your composition to visually separate keyframes in the timeline. Coloring your keyframes helps you to organize, identify, and quickly locate critical components of your composition. You can also use the color labels to quickly select keyframes with the same color group.
To set or change the keyframe colors:
Keyframe label colors are shared with layers and other objects in AfterEffects. You can customize and set these label colors according to your preference.
You can use the keyframes colors as the basis for a selection in the Timeline panel. Use only a single keyframe to quickly choose keyframes from the same color group in selected or multiple layers.
Right-click the keyframe > Select Keyframe Label Group.
On Selected Layers
Select the keyframes with the same label group on selected layers.
On All Layers
Select the keyframes with the same label group on all layers in the composition.
Visible Keyframes on Selected Layers
Select only visible keyframes with the same label group on all layers in the composition. Visible keyframes are keyframes on properties that are currently twirled open in the Timeline panel.
Visible Keyframes on All Layers
Select only visible keyframes with the same label group on all layers in the composition.
To quickly select only visible keyframes with the same label group on all layers in the composition, you can also choose Edit > Label > Select Label Group.
When you click the stopwatch button to deactivate it, keyframes for that property are permanently removed and the value of that property becomes the value at the current time. You cannot restore deleted keyframes by clicking the stopwatch button again. Deleting all keyframes does not delete or disable expressions.
Click the Enable Expression button to toggle the expression on and off, which toggles the keyframes off and on as a side effect.
If you accidentally delete keyframes, choose Edit > Undo.
Jeff Almasol provides a script on his redefinery website that automatically removes keyframes based on specified criteria—for example, all keyframes in the work area, all odd-numbered keyframes.