Special effects pioneer dies

[Ozzymandias]

Special effects pioneer Arthur Widmer dies at 92
 
     LOS ANGELES (AP) - A pioneer of movie special effects has died
at the age of 92.
     Arthur Widmer was known for his breakthrough work developing
Ultra Violet and "blue screen" special effects. His publicist
tells The Los Angeles Times he died of cancer last month.
     Last year, Widmer received an Academy Award for lifetime
achievement. At that time, an awards panel noted that many of
America's best-loved films would not have been possible without
Widmer's contributions.
     At Warner Brothers in the 1950's, Widmer worked on a key -- and
ultimately money-saving -- process that would blend two images shot
at different times and places. Actors could then be filmed on a
studio lot before a blue-screen background, with a Paris cafe scene
or some exotic setting added in later.

[ulthar]

I've been wanting to ask this question for a long time, and it seems relevant now.  I used to shoot double exposures with my Dad's 8mm where I used a black background.  What is the significance of the blue screen?  Why not black?

(I understand that the blue screen technique is not a true double exposure of the same film, but why blue for the 'neutral' color?)

RIP, Mr. Widmer.

[Scottie]

"What is the significance of the blue screen? Why not black? "

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I'll field this question with the greatest of ease:

You see, when you use a green or blue screen, what you're esentially trying to do is isolate the subject from its surroundings. If you take one color, and that one color happens to be your blue or green screen, you can tell the computer to get rid of all that color which leaves you with the subject. The benefit of using a blue or green screen is that those colors are so contrasty and so unique that nothing else a normal person would wear matches it. That way when you say "get rid of all the blue" to the computer, the computer doesn't get rid of that nice salmon pink shirt your art director spent so much time picking out, but instead gets rid of that color blue and leaves everything else. That way you can go into the computer with those expensive background software things and create exactly what they want your subject to be surrounded by. If you tried to do the same thing using a "black screen," what you'd end up doing is finding that where parts of the subject are in shadow and are black, those parts will disappear when you tell the computer "get rid of alll the black." Imagine in a dark scene on a "black screen" set where half of your subject's face disappears because the black from his face matches the black background. The green and blue they use are very bright and therefore very easy to isolate. You can in fact use any color you want to use as long as nothing else your subject has on matches that color; or else, bye bye subject. I hope this answers your question.

[daveblackeye15]

Long live blue screen! Without it we wouldn't have Godzilla.

Farewell...