Keyframes in After Effects: Introduction
Whenever we choose to record a real-life scene with a video camera where the objects are in motion, the video that we record is but moving pictures or “frames in motion” at a certain rate in unit (seconds) time that are measured as FPS (Frames Per Second) [Wikipedia Link for FPS].
When in digital animation realm, specifically in After Effects when we create animation videos, the same principle of FPS (Frames Per Second) applies to measure the duration and playback speed of an animation video. Animation itself on the other hand is the change of values over time for an object’s property. For instance, you can animate the Opacity Property of an object (layer) from 100% at a given time in the timeline to 0% in 1 second duration forward to make the layer fade out.
Keyframe (Controller) Icons in After Effects
The objects or their properties (that we are animating) however, require a certain set of controllers or markers to trigger and stop the motion/action of those objects.
In After Effects, Keyframes are the controllers or markers that we add for an object/layer’s property on the timeline, to mark and control the beginning and the end of a certain action in given time. Since the smallest constituent element of a video is a frame and this marker/controller sits on a frame in the timeline, the name given to it is “Keyframe”.
Usually, at least two keyframes are required to establish a change of action over time. Where one is placed at the beginning of the change, and the other one at the end with a different value (numeric value).
Following is a beginner’s guide to Keyframes in After Effects.
In this article, you’ll learn about:
Table of Contents
1. What are Keyframes in After Effects?
In Adobe After Effects, Keyframes are the markers used to set values for different types of properties for a layer. Which include motion properties such as Transform Properties namely Position (P), Rotation (R), Scale (S) Anchor Point (A) and Opacity (T), various types of effects such as Blurs, Color Correction Effects, Particle Simulations and Audio Effects etc. You can set the values for a certain property of a layer in the timeline as keyframes at different points in time to create a varying action AKA animation.
Moving a Ball from Point (A) to Point (B) in After Effects
In After Effects, keyframes for a layer’s property are added on the timeline directly under the layer and right in front of the given property. For you to create animation or motion in a certain time period, e.g. to move a Ball from Point (A) to Point (B) in 2 – Seconds, you’ll need to have two keyframes for the Position Property of the Ball Layer (As shown in the image above). Where the first keyframe marks the begin point and the second one marks the end point for Ball’s motion.
Once you put two keyframes a certain time period (e.g. 2 – seconds) apart from each other in the timeline marking the begin and end states of an object (ball), After Effects automatically figures out the in between frames creating the relevant motion/action as a result. This behavior of After Effects is known as “Interpolation”. Or in other words the values between the keyframes that we added are “interpolated”.
Check out this article for more on Interpolation – What is Keyframe Interpolation?
2. What is the Current Time Indicator (CTI)?
The Current Time Indicator (CTI) also known as the Play-head is of supreme importance when it comes to adding keyframes and changing the current value of a property keyframe. The CTI/Play-head tells you about the current time in the timeline of a composition as you’re moving forward or backward in time.
CTI (Playhead) in After Effects
The CTI/Play-head is a guitar string like object with a little triangle attached on top of it that moves forward/backward on your timeline. The CTI/Play-head essentially is After Effects’ equivalent for the seek bar icon of a digital video player (QuickTime, VLC, YouTube etc.).
For adding keyframes, you need your CTI/Play-head to be at the exact frame in timeline that you’re intending to add the keyframe on.
Check out this article for more on Adding/Removing Keyframes:
How to add/remove and navigate between keyframes in After Effects?
The S Bit Fun Fact:
The CTI/Play-head is also present for any footage (double click open from the Project Panel) and video layer (double click open from the timeline) in After Effects.
3. What are the Stopwatches for in After Effects?
Stopwatches in After Effects as the name suggests are the tools to record something over time. And that something happens to be keyframes.
The idea of stopwatches in After Effects is that any property, be it an effect, color fills or strokes, animation properties or any plugin with variable values will have a stopwatch attached to it. And any property with a stopwatch is pretty much animatable.
Stopwatches in After Effects
4. Khan's Quick Tips
– Inactive State of Stopwatches:
When the stopwatch is inactive for a layer property, the property has no keyframes (Da!). In this state If you change the value for a layer property, that value becomes the absolute value for the property or in other words, remains the same for the entire duration of the layer.
– Active State of Stopwatches:
Once you click on the stopwatch of a property however, it activates the stopwatch (it turns blue) and adds the first keyframe for that property at the current time where your CTI or Play-head is parked. And once the stopwatch is activated, it starts recording any change in the value of a property in the form of keyframes at any given time (frame in time) in the timeline i.e. off course indicated by the CTI.
– CTI on a Keyframe:
If your CTI/play-head happens to coincide with a keyframe, any change that you make in the value of the given property will not add a new keyframe (because you’re already sitting on a keyframe) but will just change the value for that keyframe.
– Stopwatch a Double-Edged Sword:
But bear in mind, stopwatches can be a double-edged swords. Where on one hand clicking on a stopwatch activates it and puts a keyframe, clicking on an already activated stopwatch (highlighted blue) will delete all the keyframes. Yes, all of them! And leaves you with an absolute current value (that stays there for the duration of the layer). So, here’s a little heads-up, don’t click on the activated (turned blue) stopwatch unless you intend to delete all the keyframes for that property.
5. What's Next?
Now that you have a much better idea of what keyframes are in After effect, let’s just push our understanding a step further. To help you have a better grasp on some of the basic and advanced topics, we’ve lined up the following articles for you: