A key frame in animation is a crucial point or frame that defines the starting or ending position of an object or character. It serves as a reference point for animators to create smooth and fluid motion. In the context of traditional cel animation, these frames are pivotal drawings that lay out the principal movements and poses of the characters or objects.
The Role of Key Frames
Key frames are the backbone of animation sequences. They represent the most significant moments or extremes of an action. Instead of drawing every single frame of a movement, animators focus on drawing the key frames first.
- Defining Poses: Key frames illustrate the primary poses or positions at specific points in time. For example, if a character is jumping, key frames would show the pose just before the jump, the pose at the peak of the jump, and the pose upon landing.
- Guiding Inbetweeners: In traditional studios, senior animators (often called 'key animators') draw the key frames. These drawings are then passed to assistant animators or 'inbetweeners' who create the drawings that fall between the key frames, filling in the motion sequence. This makes the animation process more efficient.
- Establishing Timing: The spacing and timing of key frames determine the speed and rhythm of the action. Placing key frames further apart results in faster motion, while placing them closer together results in slower motion.
Key Frames in the Cel Animation Workflow
The process using key frames was fundamental to the cel animation pipeline.
- Storyboarding and Layout: The overall action is planned.
- Key Animation: The key animators draw the essential poses on paper, which are then often transferred to transparent sheets called 'cels'. These are the key frames.
- Inbetweening: Inbetweeners draw the frames necessary to transition smoothly from one key frame to the next.
- Clean-up and Coloring: All frames (key and in-between) are cleaned up and colored on cels.
- Photography: The colored cels are placed over backgrounds and photographed frame by frame.
Key frames act as the blueprint for the entire sequence, ensuring consistency and clarity in the intended motion.
Key Frame vs. In-Between Frame
Understanding key frames is easier when contrasted with the frames they enable:
| Feature | Key Frame | In-Between Frame |
|---|---|---|
| Purpose | Defines critical poses/positions | Fills in motion between key frames |
| Drawn By | Key Animators (Senior) | Inbetweeners (Assistants) |
| Significance | Outlines the core action/timing | Creates smooth transition and fluidity |
| Quantity | Fewer (defines the 'start' and 'end' points) | More (makes up the majority of frames in a shot) |
Importance and Examples
Key frames are vital because they streamline the animation process, allowing for complex movements to be broken down into manageable steps. They ensure that the core performance or action is clearly defined before the laborious task of drawing the intermediate frames begins.
Examples of Key Frames:
- A character standing still (start) to fully extending their arm to wave (end).
- A ball resting (start) to being fully squashed on impact (end).
- An object entering the screen (start) to exiting the screen (end).
These main poses, drawn as key frames, provide the essential roadmap for creating the hundreds or thousands of drawings needed for a finished animation sequence.
