-
Chroma key problem
Hey there guys,
I’m working on a project using blue screen in Premiere Pro 2. I have keyed out pretty well using a combination of keys including: Chroma, Blue, Color and Non-Red. The issue I have is the edge of the subject (a person) is sparking. I’ve played with these four keys for hours and have tamed the edge slightly but it’s still not there yet. Do you guys have any suggestions please?
Thanks,
Roberta -
4 Replies
-
You really need to use After Effects Keylight to do a decent job of chroma keyeying.
-
Keying in PPro is actually not simple by any stretch of the imagination if you want it looking good.
You need to understand the concept of grey scale levels of what’s masked out using white to keep info, black to make transparent and grey to keep some amounts of info based on how bright or dark the grey is.
Once this idea is understood, you can use blurs to take hard found edges, white against black, to blur the shades into a form of soft grey. You will need to use nesting and multiple layers looking down on each other. One clip dedicated to gaining the majority of info, another one for finding edges with ‘find edges’ effect. You can use the colour correction effects to show a masked version of a selected secondary colour, namely the green or blue BG. It’s not as simple as using AE with Keylight.
Then there is garbage mattes…Seriously, try to get your hands on AE with Keylight!Jon Barrie
aJBprods
http://www.jonbarrie.net -
I wanted to respond with some findings that others might find helpful. The keying I am doing looks great except, as I previously said, this ringing around the subject.
On the trial shoot I did not have this problem and I know why. The only difference between shoots was that a studio coordinator insisted the director said that four lights on the blue screen must be used: two 650 watt lights, one from each side and two rectangle lights, side by side, directly over the blue screen. In the trial, only the two side lights were used and there was no ringing around the subject. So, the assumption is that light shot straight onto the blue screen reflects back onto the subject and creates ringing (or sparking) around the subject. So, I think light on the screen must be shot from the side.
Hope this helps others with this problem.
Roberta
Ps. Thanks for the other two posts. Yes, keying in Premiere is challenging. I’ve used multiple keys (non-red helps with the ringing) and garbage mattes and also, trial and error with everything else. you guys are right, I need AE to get this done. Hopefully the studio computer will be repaired soon. Thanks. -
Thanks Jon,
You are right. AE is the way to go. I’ve been struggling with mutliple keys and the key looks good but this ringing or sparking around the subject. I’m not sure I get what you’re saying about the black and grey but it’s a moot point because the borrowed computer from another studio while my studio’s non-linear editing computer is down, has been returned. So, there is nothing to key with at this time. I will have to wait until my studio’s computer is repaired, which does have AE 6.0 on it.
Thanks,
Roberta
Reply to this Discussion! Login or Sign Up