Snow White was created with cel animation, which is a traditional animation technique that was widely used before CG became commonplace. During this process, animators draw each frame at a time and then background specialist paints the background using watercolor or acrylic paint. Once complete, a drawing of a sequence is transferred to a cel, a piece of clear plastic preparing them for photography. A special animation camera called a rostrum camera (check out how one of these works here: https://en.wikipedia.org/wiki/Rostrum_camera) is then used to record the animation, and then the sequences are pieced together. You can find a more complete description of the animation process for Snow White here: http://scihi.org/snow-white-seven-cel-animated-dwarfs/ Here is another good description of cel animation in general: https://conceptartempire.com/cel-animation/