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Hi everyone,
Here I come again in need of some expert tips. The situation is quite simple, I have a character wearing a white shirt with big blue stripes against a blue key *sic*. What would be the best solution according to you?
– Thanks in advance
Ah, and I forgot. He also wears a blue jean …
π―
Roto?
Well … I guess it’s the only solution and I should start now. But first, I’m gonna cry like a baby.
π₯
A technique to use two quick rotoΓΖΓΒ’ΓβΓ’βΒ¬ΓβΓ’βΒ’s.
One simple roto on the outside done every 5 or 10 frames, where the shape is away from the edge by a number of pixels, in other words an outside garbage matte. Use this to put pure blue outside the subject.The next is to do an inside rough garbage matte to fill in the pants and tie of the subject. Again leaving a few pixel boarder. You could fill this with say red.
Pull the key, which will be based on a boarder. Copy that matte to the original live action. Salt and pepper to taste
I fail to understand… do you mean fill the blue jeans in red then key the red against the original blue screen? Surely the roto would have to be darn good. Or am I missing something here…
Difference key??? I would guess Fusion has it.
(in case you have a clean background of course)good luck with the roto tough…
Jaime
Thanks to everyone for your tips. So, I tried almost everything but the problem is that the blue parts of the character that are always the same colour as the key are on the edges, even when I try all kinds of colour corrections.
It makes it quite tricky to have a proper matte by ‘alpha-painting’ or the oh so annoying zones.
I think I can make it by combining keying and roto, but first, I’m gonna hang the technical director.Cheers
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No you don’t have to fill in the jeans perfectly at all. you want some of the boarder of the jeans so you can key them, By limiting the area to key you can actually pull a matte of a different blue (jeans) against a blue screen. Rather than cleaning up a keyed matte afterwards, you do the garbage matting first.
See image, from top to bottom. Top Left is the live action; next clean up blue screen; last a rough fill in of the talent.
[http://beta.eyeonline.com/files/bluegarbage0000.jpg%5DAll keyers work well, but the more fluctuations and changes in the blue background the wider the controls get set, therefore you start to get wholes or tearing in other areas of the subject. By pre garbage matting, only the edges exist and the keyer can be tuned to give a clean matte even on blue jeans on a blue screen.
Oh! Yes π Yes I’m a big fan of doing that, although I normally do it the other way around – start the key just for the edges, and then if you can extend it to fix holes in the FG / garbage in the BG, if not, holdout / garbage masks.
Makes more sense than the way most people seem to do it, which is to try and get the whole FG solid and the whole screen transparent, and then wonder why their edges have gone to shit…
Not sure why you’d fill the holdout area red when you could just add the mask to the result of the key but whatever π
Sorry to back the discussion up a bit, someone mentioned a tolerance key…what type of key is this and How can it be executed?
I’d like to try it.thx!
Just means a really crisp, hard key, where you keep the Tolerance slider (or whatever you keyer calls it, Screen Range in Keylight for example) down really low so it only takes out a very narrow range of colours – i.e., hopefully the blue of the screen but not the blue of the jeans π
The best keying technique to seperate between different hues imo a chroma keyer (like primatte), but with very little difference in hue you will end up getting very hard noisy edges so an option might be is a hue difference keyer, that is also good for this sort of thing but has better edges (the ultra keyer is a rgb colour difference keyer (+ min op with a chroma keyer) for hue diff see: http://www.bildfehler.de/fx/cdk.html
otherwise its the nobal art of rotoscoping…
a macro with it is made up here:
http://www.miafx.com/23/tiki-download_wiki_attachment.php?attId=100&page=Colour%20Difference
more on keying here:
http://www.miafx.com/23/tiki-index.php?page_ref_id=125
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Rafal
miafx.com – join the wiki
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