An Introduction to the 12 Principles of Animation
These were devised in the 1930s when the Walt Disney Studio needed to quickly bring up new animators up to standard as production moved from quirky shorts to full-length features such as Snow White & Bambi. These required greater consistency in style than the cartoon shorts (which could never achieve more than $15,000 each – Walt gambled that he would get a better return on a feature).
They were published in the 1978 book ‘The Illusion of Life’
ISBN-10: 0786860707 ISBN-13: 978-0786860708
Intended for animators working with pencils on paper, whose drawings would then be traced onto acetate and then colour painted on the back of the cels, the principles hold true for many other media
Alan Becker is the author of the infamous Animator vs Animation series – see his walk cycle tutorial on our walk cycles page.
The excellent resource at http://minyos.its.rmit.edu.au/aim/a_notes/anim_principles.html