Working with keyframes in Adobe After Effects is one of the easiest and most fundamental ways to add more dynamic actions to your projects and make them pop. You can create them with just a click, and adjust them almost as easily. Since they’re so valuable, you can make yourself more valuable as an artist by learning how to utilize them for your projects. Here’s how.
Since videos and animations are made up of frames, a keyframe is a mark (a diamond symbol in most cases) that’s created at a specific time for a specific layer property’s value. This can be for position (shortcut = P), scale (S), rotation (R), opacity (T), anchor point (A), or other properties in effects and plugins. Typically, at least two keyframes are used to create a change with a property’s value over time. One is placed at the beginning of your change, and one at the end with the new value.
To create a keyframe, select the layer property and click on the stopwatch.* A keyframe will appear at the current time indicator (CTI) on your selected property. Now your property is active, denoted by a blue stopwatch. When a layer property is active, any change you make to the layer value automatically adjusts the current keyframe or creates a new keyframe with that change.
When it’s inactive, there are no keyframes, and any adjustments will keep the value the same for the entire duration of the layer. To create a keyframe without changing a value, copy/paste the keyframe at your new position, or click on the gray keyframe navigation button (the gray diamond to the left of your layer).
*Tip: You can also create a keyframe by hitting alt/option + (property shortcut), or you can go up to Animate > Add (property name) keyframe.
Removing and Moving Keyframes
To remove a single keyframe, simply select it and delete, or select it and click the blue keyframe navigation button (the blue diamond to the left of your layer) and it will be removed. To remove all keyframes, click on the blue stopwatch and every keyframe will be deleted.
You can move the keyframe right or left in the timeline by just clicking and dragging it to your preferred spot.
Adjusting Keyframe Values
Twirl down the triangles next to the layer and transform properties. The blue numbers are each property’s values, as well as the value of the keyframe at that time (if there is one). You can click and drag them left or right to increase or decrease the value*, or you can click and manually type in the value you want.
If you only see one property or value, you can hit shift + (property shortcut) to bring it up, in addition to the one you’re seeing. View all your keyframes by hitting U (a.k.a. the überkey), and view all modified keyframes in your project by hitting U+U (that’s U twice).
*Tip: You can adjust the values more slowly by holding command/control while dragging, and you can adjust them more quickly by holding shift while dragging.
Interpolation (a.k.a. “tweening”) sounds fancy, but it’s basically what After Effects does between keyframes on an animation, movement, or other value change. Most of the time, AE does a fine job figuring out what should happen between keyframes, but sometimes your media can drift or move in unwanted directions or speeds because of interpolation issues. There’s a lot to go over with interpolation, but here are the broad strokes:
Spatial interpolation is how your object moves in space, and is adjusted in the main composition window. Temporal interpolation is how your object moves in time and is adjusted in the timeline (right-clicking on keyframes). There are several types of interpolation methods for both, and AE automatically sets spatial interpolation to Auto Bezier (you can change this in your settings).
To change the spatial interpolation, select a keyframe in the timeline. It should bring up the keyframe(s) as a box on your main composition window. The dotted lines are the movement paths. If you want to keep the movement straight and uniform, then keep the spatial interpolation linear. For non-linear movement, right-click on the keyframe and pick one of the other options until two solid lines with dots (a.k.a. bezier handles) appear at the ends. Drag the little dots to create your desired path shape.
Imagine you want to animate this kid down this slide and then flying off into the air. Each interpolation method makes the kid take a different path. Here are the options:
Here they are in motion:
You can see that a curved path matches the shape of the slide much better. This makes the animation look a lot more natural, so use the one that fits best with your project.
For temporal interpolation, you can keep the time change uniform with the linear (default) setting, or you can right-click on the keyframe in the timeline and set each one to gradually start and/or stop with various speeds. This is controlled with the other settings (Bezier, Continuous Bezier, Linear, Auto Bezier). You can also create a hold to keep it in place until the next one, if there is one. Here’s what each method looks like:
Finally, right-clicking and selecting “rove across time” will smooth out any inconsistent speeds between your chosen keyframes. Just select any/all keyframes you want to change and you’ll see them turn into little circles. Play it back to make sure it looks nice and smooth.
Example #1: The Ken Burns Effect
Documentary filmmaker Ken Burns is notorious for animating still photos in his films. They move from side to side, up and down, or scale up or down as the narration discusses the subject in the photo. We’re going to mimic this by adding some standard keyframes.
Import your clip into your project, then create a new composition based on that clip’s settings. Next, set the CTI to the first frame of the video and open the Transform controls. Create new keyframes for scale and position.
Now move to the last frame of the video, scale the clip up 5%, and change the position by at least 20-30 pixels to be able to notice the change. Play it back and see what you’ve got.
For the next example, we’re going to add some temporal interpolation. Take the same clip you’ve already keyframed, and select and right-click on the first set of keyframes. Go to Keyframe Assistant > Easy Ease Out. Then go to the last set and select “Easy Ease In.”
This will make the movements more gradual and natural, which is very important when you want your graphics to look well-integrated. Think of animation like a car — cars go from 0 then gradually speed up to the cruising speed, then gradually slow back down and stop. Without interpolation, animations will be more rigid. You can use this as a guide.
To make the movement curved, click on the position keyframe and go to the main composition window. Right-click the keyframe and open the keyframe interpolation window. Set the spatial interpolation to Bezier, then drag the little dot for each keyframe to create the motion path you want. Play it back with the curved paths and see what you think.
Now that you’ve done some basic keyframing, you can experiment with other interpolation types and more complex movements and animations. Once you get more comfortable with keyframing, you can basically move and animate anything you can think of!
Top Image: Slide From Crawl Construction on Modern Kids Playground by joshhhab and Superhero Kid by alphaspirit