A History of Compositing

This presentation taught use the evaluation of composting technology and the green screen

It all started with Georges Méliès, who's 1898 film Un Homme De Tête (Four Heads are better than one), used the Matte Shot. This technique of painting a piece of glass black to blackout certain parts of each frame so that no light would get to it left these parts unexposed. After this, he would rewind the film and use the reverse order of painting the other parts of the frame black and result in a double exposure that could combine multiple shots all inside the camera. http://www.youtube.com/watch?v=Q8RTn3jTQiM

This technique was also used in The Great Train Robbery (1903) by  Edwin S. Porter but this time not as a dilibrate illusion in the form of a magic trick, but to fool the audience to believe actors were part of a fictional location with trains in the background that were never actually present.

As film quickly became more popular, Norman Dawn used the Glass Shot technique to make sets seem bigger, apparent, or different without the cost of construction and building work. this worked by producing  paintings (such as a building) on a glass sheet that could be small and be structured closer to the camera and give the effect that it is grand in and to scale with the actors in the background. The issues with this was that the  paintings had to be ready on set, and Dawn solved this problem by painting the space black, and allowing artists to take their time with the paintings. The only other problem was that actors couldn't ever be in front of the image or house, and restricted movements as the camera couldn't move or pan. None the less it was a popular technique that was used throughout Hollywood's golden age and even sometimes used today. http://www.youtube.com/watch?v=f1V8J2Nz9Vc

The Black Screen used the traveling matte that was introduced by Frank Williams in 1918 and used in the 1927 film "Sunrise: the song of two humans." This process was were subjects were photographed against a black background and the contrast was increased until a sharp black and white, vivid image could be seen where the subject would be a pure white silhouette. This was used as the matte called the traveling matte. John P. Fulton used this technique in 'The Invisible Man' (1933). This was accomplished by having an actor (Claude Rains) in a full black suit like a onesie, against the black background removing and putting on clothes. This allowed only the clothes to remain in shot, and was very effective, however, id did mean shadows were never present.

The Blue Screen was introduced in 1925 by C.Dodge Dunning, and first used in 1933 in King Kong by Merian C. Cooper and Ernest B. Schoedsack. This process lit the subject yellow against a blue screen and using filters and dyes created traveling mattes. The lighting never matted too much in black and white films as the yellow never showed up as it was all grey-scaled. 

However,  in 1940 Larry Butler won an Academy award for his invention and introducing of a new technique in The Thief of Bagdad. This Three Stripe Technicolor process still used blue as it was the furthest colour from skin tone possible. Then taking the blue and separating the colours, Butler was able to make a silhouette matte just like Williams, and with using new technology such as the 'optical' printer could re combine these film strips. This diagram shows how he rearranged the colour stripes to remove the blue background and composite the subject onto the background, finally being able to print them as one. This still produced a blue line around the subjects at times and items like running, smoke, and other blurry effects became difficult to produce.

The yellow screen (or Sodium Vapor process), 
was created by Petro Vlahos in the mid 50's for Walt Disney (showed here in Mary Poppins). This used normally lit actors on a white screen which was lit using sodium vapor lights, and using a 'specially coated prism' (the triangle) in a technicolor camera could identify the exact wave length of the sodium vapor and process it on a black and white film automatically creating a traveling matte.

The rest of the unaffected image (the subjects and actors) were then processed through the normal three stripe technicolor way. It was first used in 1961's The Parent Trap, but it was 1964's Marry Poppins that won the Academy Award for best special effects. Disney owned the only camera and rented it at expensive costs, meaning other studios had to find yet another alternative.

MGM hired Vlahos to improve their blue screen technique and after six months of studying he had success.

As most colours conatain the same amount of blue and green in what makes the colour, Vlahos ran the footage through a green cancellation process and ran that film under a blue light to create "Blue separation matte" where after a long process essentially  was made a synthetic blue separation from the rest of the combined image.

This process required 12 film elements from start to finish but managed to rid of the downside of the blue outline that was there previously.

This process was so popular it was used for 40 years, until the invention of digital compositing.

A keyer is a mathematical based process in which the range of colours could be made transparent. Green was used because it was cheaper, easier, electronic displays could pick it up easier, and blue often matched the sky in exterior scenes.


As digital cameras took over film, the Bayer System (right) was much more sensitive to the green in shooting as their is twice as many as blue or red. This made it easier to remove green from the spectrum although blue is still used depending on the scene (For example Sam Raimi's 2002 Spider-man, blue screen had to be used for the green coloured green goblin and green screen had to be used of Spider-man as he has blue on his costume).

Today's software can create completely realistic CGI and composting that is 100% believable and often not even noticeable, but it has taken over a decade of development and though composting I believe has reached its peak in the art of illusion, it can still be obvious in some films if lighting is not correct and the editor has applied not colour correction techniques.