In our last blog we began discussing the journey, from the late 19th century, towards our modern day green screens. Now we know about matte technique, the glass shot and the black screen but what came next?
The blue screen, also known as the Dunning Process after C. Dodge Dunning, rebelled against the black screen. As opposed to the Williams Process the blue screen made use of contrasting colours instead of focussing on black and white. For this process coloured lights were used: blue was used to colour the background while yellow was used to light up the foreground and subject. It was discovered that these colours could be split apart, when displayed in black and white, to create travelling mattes, as seen with the black screen. This technique was first used in the 1933 film King Kong.
After the realisation that different colours can be manipulated in certain ways for black and white films this knowledge was further developed to create the yellow screen. This technique, developed in the 1950s and used extensively by Walt Disney Studios in the 1960s and 1970s, required sodium vapour. The process involved the actors and foreground, which were lit normally, standing in front of a sodium vapour lit screen. The specific wavelength of the sodium vapour light was split and recaptured on special black and white film, automatically creating a travelling matte. The most iconic film created using the yellow screen technique is Disney's Mary Poppins.
As Walt Disney Studios were in possession of the only sodium vapour camera there are very few non-Disney films created using the yellow screen. Also, because of this, other studios continued to develop the techniques of the blue screen which, eventually, led to the conception of the green screen. The green screen technique, also known as the chroma key, built on the blue screen technique's knowledge and manipulation of colour. As technology has advanced, so too have these filmmaking techniques. The modern day green screen is primarily used to create post-production special effects, such as wizard's flying on broomsticks and superheroes effortlessly flying through the air. Although there are people who believe the simple art of filmmaking has been lost, I think even the cynics would agree that special effects - from the matte technique to modern day, post-production CGI - have undergone an amazing transformation.