[shah alam]

I spoke to our DoP about the blue/greenscreen lighting and he agreed the use of full CTB (colour temperature blue) that we used almost certainly reduced overall illumination by about a stop. For our shoot that was fine as we were only lighting a small three metre wide screen (enough to cover two guys in alien makeup and costume).

He also said that for a large stage shoot the screens may well be lit using HMI’s, that would create a blue cast which would in effect do something similar to gelling the lights (not to the same level though), although this would only work for bluescreens and not greenscreens.

[shah alam]

I’m not sure if gelling lights blue for illuminating bluescreens is common practice or not, it was just an idea that our DoP put into practice; he may have got the idea from a cinematography resource. I’ll ask him next time I speak with him; we’ve got a greenscreen shoot this coming wednesday so I’ll ask him then.

I haven’t tried the plugin myself, so can’t offer any advice on how well it works. I was about to download the trial version a few months ago but never got round to it as I got pretty good results by just blurring the blue channel

[shah alam]

I’ve done a fair bit of keying with DV footage for our film and have found that greenscreen will normally produce better results than blue (I think that blue gets sub-sampled more than green). If however your footage is bluescreen you could try blurring the blue channel a little, even just by 1 pixel and that should help soften the blocky edges enough to get a better matte edge. Apart from that, we found that if a little time is spent while lighting the blue/green screen so that it’s vibrant (the lights that we lit the screen with, we actually gelled them blue) will really help in post.

Here’s a link that I picked up from one of the fxguide podcasts: http://www.dvgarage.com/prod/prod.php?prod=dvmatteae I think it works by combining a chromakey with a lumakey (the luma information in DV isn’t sub-sampled) that helps produce good edges.

Good luck with it.

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