These days, we couldn't imagine a film without special effects, CGI and the abundant use of green screens. These amazing effects are taken for granted in big-budget movies but they weren't always around. We may laugh now when we watch an old film with comparably bad special effects but the art of illusion and trickery in cinema dates back further than you might think.
In 1898 Georges Méliès developed a visual trick technique which established the foundations of modern day special effects. The use of mattes for multiple exposures was a technique which combined multiple shots to create an unusual image. This technique was used, before the invention of modern cameras, to create the illusion of larger scenes, or more realistic settings, than were physically achievable. The technique is demonstrated in Edwin S. Porter's 1903 film The Great Train Robbery.
This technique involves painting elements of the scenery or setting onto a piece of glass and placing the glass between the subject and the camera. Filmmaker Norman Dawn used this technique to allow sets to look bigger and much more elaborate than they actually were. However, as the painted glass was a physical object, and not a post-production effect, it took time to paint and install them. Although this technique was not seamless, elements of it are still used within modern-day cinema.
During the height of classic Hollywood the black screen technique, also known as the Williams Process, was developed, paving the way for the modern day green screen. As opposed to the matte technique, the black screen aimed to blur the line between live action and the effects added to the film. The concept of the black screen, or travelling matte, was displayed in F.W. Murnau's 1927 film Sunrise where subjects were filmed against a pure black background. The film was then copied onto high contrast negatives until the black and white silhouettes emerged: this technique was far more advanced than the matte technique as the subjects appeared as though they were moving through the frames fairly smoothly.