Scientific Theory of Animation-Persistence of Vision 

Animation is an art and science; it’s a new art form that evolved from technical innovations in frame projector science. Learning the concept of animation will be easy by learning the scientific principle that helps animation work. So what is that principle? It’s very simple and is based on a simple theory-persistence of vision, according to which, a human eye can retain the images for more time when more images are projected at high speed. That means a human eye requires some time to conceive a single image. When multiple images are shown within a less span of time, the eye will retain all images and the result is an illusion-That is Animation.


For example, multimedia images carries an action printed on them like a rolling ball, with some replacement in the positions of successive rolling ball, rolling in a path in all images. Consider that total number of images is 24, and the time images are exposed to eye is 1 second. That means on an average, each image is exposed one twenty four time of a second and within the next one twenty fourth of a second, the second image will follow. This time it is not enough to grasp all information about an image for the eyes, so the image will be retained for a longer time in memory. When these multiple number of images are retained in the memory, the replacement in their position causes an illusion of motion, like that of a ball rolling.

Why 24 Frames Per Second?


You can even try 12 frames per second but the action you see will not be appealing. For live action movies the applicable rate is 30 frames per second and for TV animation. any drawing that is produced for an action will be exposed twice. That means, to produce a second of animated action you will need 12 drawings which is equal to 24 frames. The reason is to get some mileage. For features, exposure rate will be in 1’s and it all depends in what kind of an action whether it is a slow one or a fast one. For example, a fast running character should be exposed in 1’s. So that action looks very kinetic. This entire pattern comes under the concept of animation timing. Timing play a major role in animation, especially, in helping it defy the live action movies in extreme action like, Tom and Jerry’s cut to chase sequences. You might have wondered what makes TOM & JERRY performs those extreme action and attain an elastic personality. This is the result of proper application of animation timing.

How to Measure Length of Animation?

Animation is measured in footage. In animation, footage is nothing but length of animation measured in feet. Normally one foot of animation is equal to the length of 16 frames of animation. That means one second of animation is equal to one half feet.

  • 1 foot = 16 frames
  • 1 sec animation=24 frames = 1 1/2 feet.

Frame Rates:

The frame rate that you work at is a very important factor in the final quality of your animation. The frame rate determines how many frames per second are displayed when you playback your animation. If you set the frame rate too high, you have to produce too many drawings. If you set it too low, your animation will look choppy.

12 frames per second (FPS) are recommended for drawn animation. This is one half of the frame rate used by film. This is referred to as ‘drawing on twos’

Typical Frame Rates:

12 fps: The majority of cartoon animation is drawn on twos. When put on film, the frames are exposed twice to make 24 fps. In our case, we can simply play back at 12 fps.

15 fps: Less typical would be animation drawn for twos on video.

24 fps: Film

25 fps: Pal Phase Alternate Line  (European) Television.

29.97 fps: When color was added to the television standard, a slight adjustment had to be made to accommodate the extra signal used for color. The video still plays at 30 fps, but occasionally a frame has to be dropped to keep up. This is called ‘Drop frame’

30 fps: Black and White NTSC National Television System Committee (US) Television.