How to decide between Blue Screen or Green Screen?

Tim Joy

Tim Joy

Veteran
Don't know if this is really more of an FX question, but all the smart guys seem to hang out here...:)


Other than the color of background, like if there's a green forest that's similar to the greenscreen, you would want a bluescreen, right?

What about indoors? I need to buy one or the other, so which is most used/ better? Green or blue?
 
in video (unless you got some monster camera that shoot 4:4:4 ) you need to use green, because it is the only color that is coded at full resolution.
red and blue are half resolution (at least in DV 4:2:0 or 4:1:1) and you do not want to deal with a color background that is only 360x288 pixel.

If you cannot use green , try blue with a direct capture from camera to some card allowing high quality low compression.
 
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If your subject has some amount of green in it, use blue. Some blue, use green.

The subject dictates the background color not vice versa.
 
i think the lights you're using have a significant influence on what screen you should use as well. ie: HMI or daylight use Blue. Tungsten/3200K use Green. i'm no expert, but I attended a Blue/Green screen seminar last year presented by a expert. if you want i can email you the VFX Super's PDF presentation. there's loads of helpful info in it. just PM me your email address or let me know if someone knows how i can upload a PDF to this forum.
 
To use 7D for green screen is really playing it for it's worst qualities and neglecting it's good. The encoding is 4:2:0 meaning with it's already bad resolved resolution you'll have less than SD res to key from and you cannot really use it's strong point over ordinary camcorders; short and shallow DoF as that also makes it hard to pull a good key. Rent/borrow a HD camcorder for that day and preferably capture directly to a computer as uncompressed as the box can muster.
 
Michael B. McGee said:
i think the lights you're using have a significant influence on what screen you should use as well. ie: HMI or daylight use Blue. Tungsten/3200K use Green. i'm no expert, but I attended a Blue/Green screen seminar last year presented by a expert. if you want i can email you the VFX Super's PDF presentation. there's loads of helpful info in it. just PM me your email address or let me know if someone knows how i can upload a PDF to this forum.
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Nice PDF Greenscreen guide. Thanks DOWNLOAD HERE

Martti Ekstrand said:
To use 7D for green screen is really playing it for it's worst qualities and neglecting it's good. The encoding is 4:2:0 meaning with it's already bad resolved resolution you'll have less than SD res to key from and you cannot really use it's strong point over ordinary camcorders; short and shallow DoF as that also makes it hard to pull a good key. Rent/borrow a HD camcorder for that day and preferably capture directly to a computer as uncompressed as the box can muster.
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True. It's a quick shot though, and I think it will be fine for this. If I were doing more extensive work, I'd get the proper camera. The results I saw from Barry's challenge tests were better than even he expected with the 7d, and seemed to depend as much on the talent of the person doing it as it did the camera that was used.
 
Well, I've been keying stuff for 15 odd years and I'd rather poke my ey... nah, I rather rotoscope a short scene than trying to pull a decent key from any footage mangled through a long GOP 4:2:0 encoding. If you really must do a key consider doing a luma key against black or white background (depending on plate subject) - at least then you get the full resolution the camera can produce. A garbage matte to hold out the dark / bright parts of the foreground object and you are probably ending up with a better looking comp than a green screen.
 
There's a few other factors involved in the color based on your subject. For dark-skinned people or people with very blonde hair, you may find you're better off with blue. In other cases green will tend to work better, all other factors being equal.
 
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