Special and Visual Effects : Difference between Blue/green screen?

Difference between Blue/green screen?

Why does certain movies use blue screen and others green screen for their
special effects? Does the one have an advantage over the other?

Re: Difference between Blue/green screen?

Presumably it depends on what colour costumes the actors are wearing: shades of blue or green would be rendered near invisible against their respective backgrounds. Although, I did read somewhere that costume designers generally try and avoid these colours in effects-heavy films. Blue and green are also furthest away from skin tone.

Re: Difference between Blue/green screen?

blue screen was the first type, and was used for simple composites like characters against a background

green screen is a more used version, and mostly used in larger vista scenes, like in the newer star wars trilogy

there's also BLACK screen, used in particle effects (see HOLLOW MAN)

Re: Difference between Blue/green screen?

Blue or green because they are very far away from red (=skin tone).

Historically, blue worked best for photo-chemical processing. It was already used during the black-and-white film era, and you could separate blue from the other colors just by filming/copying through a blue filter. It's at the end of visual spectrum at the lowest wavelength/highest energy furthest away from the reddish of skins, so doing that would not interfere with filming humans.

Green was easier to separate from other colors with electronic analog TV cameras (weather maps). It also works better with digital cameras since green needs lower light intensity and has the highest resolution there (as opposed to film, which has finer grain at blue).

Nowadays, any sufficiently small range of colors can be used. Depends on the design of the film and the color range that should be end up on film.

Reading the paragraph on matting here (http://en.wikipedia.org/wiki/Compositing) may help you to understand.

Re: Difference between Blue/green screen?

As a side note green is used in outdoor scenarios because it needs less light intensity.
Top