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Hello there
I’m working on film shooting s16mm on greenscreen and have a couple of questions: we did a pathways test on bluescreen, telecine’d via cREALITY to 1:1 files, and the grain was very unpleasant, which made for tricky keys…
The DP has been advised to go greenscreen, to improve the grain problems (plus we re-telecined the blue on a SPIRIT, which helped): is this true?
NB: we’re grading back to BW with possibly some items left in colour…After the re-telecine (SPIRIT), we outputted to D5 (instead of 1:1 files), which ws then digitised to tga’s for me: have been noticing some jaggy edges (albeit small, perhaps this is a problem when blown up to 35mm?)…. IS THIS NORMAL? and what is the best way to deal with this in the key/matte? (keying on Combutsion 4) How does jaggy translate into clean hair matte?
not sure which is the lesser evil: horrific grain or digital artefacting… err…
also: some costume questions re: greenscreen: satin has been suggested, which sounds like a headache to me (but i dont this know for sure) IS SATIN A BAD IDEA? and ARE PATTERNS to be avoided as well (e.g. plaid suits from the 30’s, chequers, pinstripes, etc.)
any advice welcomed
jungleroseFirst thing to check, has the colourist done any secondary grading, to “improve” the blue, if so, this must not be done, also check what stock is being used and make sure it is a fine grain stock.
Here’s a link:
http://www.fischeredit.com/post/green/More links from fxguide:
http://www.fxguide.com/modules.php?op=modload&name=Web_Links&file=index&l_op=viewlink&cid=12and
http://www.fxguide.com/fxtips-45.html
The grain problems you have are probably due to the 16 mm film you are using. You would be better off using 35. But I guess that is a budget issue?
And as Paul said, don’t ever use any secondary grading to “improve” your footage. You will need 2 passes. One pass with the actual graded footage and a secondary pass left “flat” for keying. Or if you just use the flat pass and match that to your background.Cheers
What version of combustion are you using? You might consider using a third party keyer as the ones coming with combustion itself are pretty basic, although the latest version has the diamond keyer… pretty interresting but there are even better keyers out there.
junglerose wrote:and any advice re: satin/patterns to avoid with this?much appreciated
I would strongly advice against using satin. It is a reflective material ie. you will get unwanted highlights. What you will want is a bluescreen that is as even as possible and the satin material won’t help you. There are special cloths that you can rent especially made for the task. Get one of those. And while we are talking about even or not. Make sure that the bluescreen is evenly lit. That will help you a lot later on when keying. Good luck.
One other question, what res are you working at? If it’s 2k, then that is why C-reality gives a better key, as the Spirit is only 2k on the luminance channel, the chroma signal being processed at 1k.
If you mean satin as costumes for talent, then it can be a problem since it’s reflective and will pick up lots of the green which diffuses off the backdrop. Depends a lot on lighting, but if you end up with green highlights/sheens on shoulders and arms obviously the keyer might pick them up. If you’ve got a really well lit greenscreen you’ll probably be able to differentiate though, the green from the screen should be a lot more saturated.
Checks and stripes should be okay as long as the video never goes to a composite format.
HD D5 is intra-frame compressed at 4:1 or 5:1 and is 4:2:2 so it’s not going to be ideal but you should be able to key fine if you blur the chroma first, like this: http://www.fxguide.com/fxtips-223.html.
Good luck!
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