As you have probably gathered, animation is time consuming work! Traditionally, when large animations were being created, the senior artists would draw the main frames of animation, and junior artists would draw the frames inbetween.
For example, when a character jumps over a fence, the senior artists might draw the character just about to jump, and then draw the landing at the other side. The junior artists would then draw the frames inbetween.
These main frames drawn by senior artists became known as keyframes.
Keyframes in the Computer Age
With the advent of computers, it became easier and easier for anyone to create an animation. Computer applications such as Macromedia Flash allowed people without training to start making their own animated sequences. One reason why animations were easier to make was because of a computer's ability to "fill in the gaps" of a animated sequence using keyframes.
In computer animation programs, the term keyframe now means the start and end points of an animation. The artist creates the start point, specifies where the animation should end, and the computer builds the frames in between, making animation so much easier! And keyframes don't just specify movement; they might define a change of colour from red to blue, or an increase in size, or even a change of shape. All of this can be done with a few clicks of a mouse or a few lines of code.
On the next page, you'll see some examples of keyframes in action.