He could of used green.

We watched a programme about how the media perpetuates lies.

But I didn't believe it.

Why did greenscreen replace bluescreen? I notice it happened when digital effects came in, but the whole reason why blue was used (I thought) was that it was as far removed as possible from caucasian fleshtones. When computers arrived, did pink people change colour?

I guess (off the top of my head) that it was because the technology became more accurate at colour selection, and green has a higher luminosity, affording better edge resolution.

That seems plausible :-)

Grey, of course, is the best colour, these days. Thanks to Truematte.

?

It's just very reflective cloth, that looks grey when not illuminated.

bluescreen is still used, as anyone who has seen the behind the scenes footage of the phantom menace will know. i dont think it makes much difference if you use blue or green, it possibly depends on other colours used in the scene and the palette of the film in general

Either technology is getting better, or people are getting better at doing it, but you rarely see the nasty shimmering effect on TV chromakey recently.

Mind you, it was always possible. Look at Knightmare in 1987 - perfect.

Speaking of Knightmare - I always wondered if they used a big soundstage with several connecting sets and played the game in 'real time'. Or (more likely) did the poor contestants have to wait around while the chromakey, props and sound effects were set up for each individual 'room'.

And isn't green chromakey more popular now because people are more likely to wear blue clothes than green?

One room - they had to wait for hours sometimes whilst they set it all up :-)

See www.knightmare.com for loads of Knightmare stuff. Look in the pictures section, under behind the scenes.

I assume you're referring to CSO, or Colour Seperation Overlay? Only filthy ITV-watching estate children call it Chromakey.

But seriously folks, some of the poorest bluscreen work I've ever seen is in Star Wars ROTJ, when Luke's in the pit with the monster. It's really badly done, and wasn't corrected when Lucas did all his digital jiggery-pokery a few years back.

Ooooh, yes, CSO, I remember.
Some piss-poor blue-screen was also done on Voyager. I find it strange that a 14 year old show on video-tape somehow managed it better than a high-budget Hollywood production.

Why don't they use white? Then any colour wouldn't be losed or changed!

Any pure colour would work for CSO as long as it didn't feature in the foreground. The extremely bright blue and green are frequently used because these colours aren't commonly found in nature or presenters' shirts. There are exceptions of course; Kermit The Frog couldn't be photographed in front of green screen because he'd disappear.

I would've thought that white would be an difficult colour to use because you'd lose anything white, such as shirts, paper, eyeballs, etc.

I also learnt that Frankie Howerd was once photographed in front of a yellow screen for a sketch where he rode a camel in the middle of the desert.

....and dear old Francis was a paedophile as well, of course. 'Ere, mush!

so what do they do when they a need a Green tree and a blue sky? What about a turquoise background!?

You superimpose the blue sky in afterwards :-)