Blue/Green Screens

4 replies [Last post]
SM1
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Joined: Apr 29 2002

Has anyone out there any good ideas on creating an easy uniformed Blue screen background. I have tried filming against a blue painted wall but I when it comes to removing this in production I can still see areas that the Chroma Keying has not removed. I understand that the lighting has to be good, so not to cast any shadows, and this is where my problem lies I can`t afford expensive lighting. Any thoughts !!

DAVE M
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Joined: May 17 1999

We use a bolt of blue cloth. We use paper (A4) on the floor so that we can chuck it away when it's dirty

Play with your system and identify several hues that will work with it. (Some systems are less flexible than others)

Visit a fabric warehouse and buy a sample that is close, getting a shed load if it checks out ok.

Lighting has to be consistent and flat. Don't let your subject get any reflected light from the background.

you can buy photographic b'ground paper in a shade near to what you want Try a search to find the shade.

Anonymous

Lastolite make a 10x24 or 10x12 feet green or blue screen material. This is the correct shade of blue/green also.
Cost is £140 inc VAT and £180 for the bigger one.

Both have a hem so you put them on support poles, I am buying one myself on Friday.

Lighting is VERY important, evenly lit with difusers on the lights, also as Dave mentioned, don't let your presenter/actor get any closer than about 8 feet to the background as green/blue reflections hit their back, also to make it perfect use straw coloured (thanks D.F) filters on two lights, one either side of the actor aimed at their back, this cancells out the blue outline one normally gets after keying out the background. Not sure the filter colour for green though.

Also from my past experience as a photogapher I would imagine that a large apperture would help, i.e. a short depth of field.

Good look.

sharkey
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Joined: Apr 19 2002

If you go for green screen, use a magenta gel on the backlight. Not too strong though or you'll get a white halo around your subject.

Also the comment about depth of field is very valid, the idea is that the background will be out of focus when your subject is in focus. Th blurring of the background due to depth of field then helps your screen's uniformity by evening out small irregularities.

Sharkey

Anonymous

Thanks Sharkey for the "Megenta" bit, didn't know that.