The idea for doing animation was born from the huge success of the film "The Haunted Hotel", released by Vitagraph and directed by J. Stuart Blackton. It premiered in Paris in April 1907 and immediately there was a demand for more films using its incredible object animation techniques. According to a story told by Arnaud in 1922, Gaumont had ordered his staff to figure out the "mystery of 'The Haunted Hotel'." Cohl studied the film frame by frame, and in this way discovered the techniques of animation.
...Gaumont's Emile Cohl created the first fully animated film, Fantasmagorie(1908), and in the process lifted cartoons out of the realm of trick films and started them on the path toward animated features. The two-minute film Fantasmagorie (alternatively, in English: A Fantasy, Black and White, or Metamorphosis) is made up on approximately 700 double-exposed drawings, using what is known as a "chalk-line effect", a technique probably borrowed from early animator James Stuart Blackton...
Technique of the film
To make his film, Cohl placed each drawing on an illuminated glass plate and then traced the next drawing-with variations-on top of it until he had some 700 drawings. This simple technique produced consistent movement and continuity between the drawings, and allowed just Cohl and a camera assistant to create the film. In those days, chalkboard caricaturists were common attractions and the characters in the film look as though they've been drawn on a chalkboard, but it's an illusion. By filming black lines on paper and then printing in negative Cohl makes his animations appear to be chalk drawings.