History of Greenscreen/Chroma Keying

[kingkezz]

I'm doing an assignment on the history of green screen - how it works etc and was wondering if anyone knew anything about it, any books on it, web pages etc.

I'd like to know all about it - when it was first used etc, and exactly how the process works.

 

[Blue Velvet]

Here is a start.
http://en.wikipedia.org/wiki/Bluescreen

 

[Proto Media]

History lesson

Im no expert, but from what Ive heard and read and seen, this is what I can piece together.

I am pretty sure bluescreen was the brainchild of the early ILM for the first star wars film. They used a very primative version where they were actually just pulling out the blue tube from the camera. (this is the part im not sure of) so in the olden days it was really really really important to have a solid, uniform blue so that when they pulled the tube, all the blue data would dissapear and they could then composite the resulting shot over a different background. This was very cutting edge stuff back then as no one had really composited shots this way before star wars, and was part of the reason star wars was soooo revolutionary.

as you probably know, blue and green are the most commonly used colors, because of RGB. Im sure that you know of the RGB color space, and so green and blue are the easiest colors to pull because they have a dedicated channel, vs other colors which are a mixture of either 2 or all 3. Some people even use red to key (particularly if the shot being keyed is intended to be a nighttime shot. Red normally isnt used becuase there is red present in skin tones and will key that too, but for night shots it changes everything and actually red works quite nicely. alright im running out of things to say, hopefully this can point you in the right direction and get your research going. Good luck.

-Ryan

 

[aloofman]

Im no expert, but from what Ive heard and read and seen, this is what I can piece together.

I am pretty sure bluescreen was the brainchild of the early ILM for the first star wars film. They used a very primative version where they were actually just pulling out the blue tube from the camera. (this is the part im not sure of) so in the olden days it was really really really important to have a solid, uniform blue so that when they pulled the tube, all the blue data would dissapear and they could then composite the resulting shot over a different background. This was very cutting edge stuff back then as no one had really composited shots this way before star wars, and was part of the reason star wars was soooo revolutionary.

I believe the first Star Wars trilogy used travelling mattes rather than bluescreens. It was a complicated procedure because the foreground and backgrounds were printed on separate passes on each film frame. ILM's innovation was to come up with techniques and hardware that enabled them to do this much faster than was previously possible. Without it, very complex scenes like the space battles would have taken far more time and money.

Way back in the really old days, the mattes were stationary, but still printed separately on the film. Many of the old epics like the Charlton Heston version of the The Ten Commandments used it to make backgrounds to create sets that were too large to physically build. The shot near the end of Raiders of the Lost Ark that shows a wide shot of the ark-opening ceremony with the dark desert around it was done the same way.