“Whoever wishes to foresee the future, must consult the past” - Machiavelli
Compositing is a technique of combining at least two source images to create an integrated image.
When you think of vfx you may think of big abstract, out of this planet, shots. But special effects can mean anything. Before your greenscreen there were simple things like multiple exposure for example.
One of the first composites was done around 1898 by Georges Melies. In his film ‘Four Heads Are Better Than One’ he used mattes for multiple exposures. It was as simple as blocking out parts of the frame using a piece of glass that was painted black, to block out the light and prevent the film from being exposed. Then you would rewind the film, and matte the parts already exposed and film again but only exposing the previously matted parts. Seems like a very simple process but you have to imagine that precision was key for this trick to work.
“In order to make film behave the way we experience the world, visual trickery had to be done.”
That thought kept pushing the filmmakers to create more and more advanced and visually pleasing ways to make their films.
Next came the Glass shot. A technique in which you painted the elements directly on glass, and then placed that in between the subject and the camera. Like old fashioned Photoshop. With the glass shots came issues, the glass paintings had to be ready on set, Norman Dawn solved this problem by painting the glass black and treating it like a matte shot. That gave the artists extra time to create their paintings. The problem with matte paintings was that the camera had to stay perfectly still, and nothing could cross the matte line. “the ‘hopefully’ invisible line between the live action and the matte painting.”
Here is where the black screen comes into play. “The travelling matte”, a process patented by Frank Williams in 1918. It was a process in which the subjects were photographes against a pure black background. They would then copy the film to a high contrast negatives until a black and white silhouette emerged. This silhouette was used as the matte. Called a travelling matte because it moved throughout the frame.
The Dunning Process. In this process you would use coloured lights. Lighting the background screen blue and the foreground yellow. Using dyes and filters, the lights could be split apart to create travelling mattes. The first time the Dunning Process came into play was on the set of King Kong in 1933. But the Dunning Process could only be used in black and white films, the coloured film needed a new, more advanced technique.
Special effects artist, Larry Butler came up with an idea to shoot the subject on a blue screen, blue because it is the farthest away from skin tones. After separating the negatives Butler was able to create a silhouette matte just like with Williams process. Then using an optical printer he could combine multiple film strips into one.He would first remove the blue background from the foreground plate, using the negative of the travelling matte, remove the foreground space from the background, and combine both foreground and background plates together. The process proved to be very time consuming as it involved so many steps using the optical printer, and it still had the issue where the blue line would be visible in most of the shots.
Then after years of experimenting there came the Sodium vapor process. It was nothing more than actors who were lit normally, standing in front of a white screen which was lit by powerful sodium vapor lights. Because it emits a very specific wavelength and nothing else. They used a specially coated prism in a three strip Technicolor camera the very specific wavelength of the light was split off and captured on a black and white film. Automatically creating the black and white travelling matte. The remaining light was captured by a regular three strip Technicolour Film which remained unaffected by the sodium vapor lights. “This techinique produced some of the best travelling mattes of the time and was used by Disney...” There were many benefits of using this technique, and only one problem. ONly one sodium vapor prism was ever made. ONly one camera that was capable of this process, Disney owned the camera and they didn’t rent it cheap.
Then Petro Vlahos came up with a technique called the Colour Difference Matte. It’s a very complicated process, it required 12 film elements to get from the composite negative to the composite internegative. But it solved the edge and fine detail problems that doomed the blue screen. It became so successful is remained popular for almost forty years.
When we enter the digital world, we turn green. Why green? Well greenscreen is easier and cheaper to light than blue, green registers brighter on electronic displays, works well for outdoor shoots where blue can blend with the sky, and bright green is less common in costumes than blue is. Cameras nowadays are much more sensitive to the green part of the spectrum, this makes pulling a matte from a greenscreen a little easier. Blue is still commonly used, depending on the needs of the shot.
“There are cinics today that believe modern film is too reliant on CGI and that we should return to a simpler form of real filmmaking…. But, that era never existed - filmmakers from the very beginning have sought to push the medium with special effects.”
“The undeniable truth about filmmaking is the only thing that matters is what’s on that screen.”
“... it’s all about creating a window onto another world. A world where each of us can find our dreams our fears and ourselves. All these effects we have are just tools to help us get there… And we have some fantastic tools, so use them, and make something great.”
