CEL ANIMATION
A cel, short for celluloid, is a transparent sheet on which objects are drawn or painted for traditional, hand-drawn animation. Every thing has its own frame such as the background and characters.
the invention of this technique is often credited to John Randolph Bray and Earl Hurd in 1914.
cel animation allows some parts of each frame to be repeated frame to frame which saves a lot of time as you're not drawing everything out again
Cel animation also removed the jittering aspect of animations as it allowed for each frame to be more exact.
ADVANTAGES- saves time, saves money and effort as you dont need to redraw everything, removed jittering effect.
DISADVANTAGES - requires a high drawing skill, very complex process which requires high skill, still needs to be photographed and put on film.
this video is a history of cel animation .