Green screen, chroma keyer, and mask...

newUzer wrote on 6/19/2009, 9:05 AM
Hello,

Just did a quick shoot recently and used a green screen behind my talent, and left the rest for a bezier mask in post. What I found was that one has to be really careful with edge blur in the chroma keyer filter because the edge of the mask begins to show up. I assume this is because mask is applied first and then key, whereas it would be better to come up with a workflow that does key first and then mask. Any thoughts?

Comments

rs170a wrote on 6/19/2009, 10:28 AM
I always do masking after I've gotten my keying done.

Mike
JohnnyRoy wrote on 6/19/2009, 10:31 AM
I never feather the mask when using it as a garbage matte. Just leave it as a hard edge and you won't see it. You wouldn't want your keyed talent to start fading into it anyway. It should be a hard edge that no keyed object comes close to.

~jr
newUzer wrote on 6/19/2009, 11:38 AM
Hmm....I thought I was doing things correctly, but as I read between the lines of your post, and the one above, it looks like using the bezier mask in event pan/crop as a garbage mask, and the chroma keyer as a Track FX, is the wrong way to go about this. So, what is the proper workflow to key out the green behind the talent, and dispense with the garbage that the green screen doesn't cover up?
rs170a wrote on 6/19/2009, 11:51 AM
I always do chroma-keys at the event (i.e. clip) level instead of track level and save it as a preset after I'm done with it.
That way, if I'm keying another clip with the same person and location, I just call up the preset.
Then I open the Pan/Crop window and add a bezier mask(s) to get rid of any unwanted garbage.
This can also be saved as a preset.

Mike
JohnnyRoy wrote on 6/19/2009, 11:55 AM
I agree with Mike. Place the key on the event not the track and I believe you will get better results.

~jr
digitalelf wrote on 6/19/2009, 11:56 AM
You might navigate here:http://www.digitaljuice.com/dj_training/detail.asp?sid=355&sortby=&page=1&rpid=0&rvid=0&swid=0 and view this short video. I haven't gotten into keying yet, but this makes it look fun and relatively simple!

Michael M