Mysterious white shadows under arms of keyed subject

Adobe After Effects

Mysterious white shadows under arms of keyed subject

Posted by Dan Caz on May 24, 2012 at 8:00 pm

I am having this problem in both Premiere using Ultra Key and AE using keylight. Almost everytime I key out a subject and clean everything up as best I can there is this white matter that appears between the arms and body. The closer the arm is to the body the white joins between the two. I don’t know how to get rid of it. Is this a lighting issue?

Here is a link to some screen shots
4200_whitematter.jpg.zip

Thanks

Daniel Caza

Dan Caz replied 14 years, 2 months ago 2 Members · 5 Replies
5 Replies

John Cuevas
May 25, 2012 at 12:11 pm

You posted the result, how about a still of the problematic green screen shot.

Johnny Cuevas, Editor
Thinkck.com

“I have not failed 700 times. I have succeeded in proving that those 700 ways will not work. When I have eliminated the ways that will not work, I will find the way that will work.”
—THOMAS EDISON on inventing the light bulb.
Dan Caz
May 25, 2012 at 2:52 pm

Here is a green screen shot. It’s not perfectly lit but with a garbage matte the differing shades aren’t a much of a problem. I am shooting with a sony hdr-sr11, a handycam basically but it shoots hd.

Image here:
4203_greenscreen.jpg.zip

Thanks

Dan Caz
John Cuevas
May 25, 2012 at 5:05 pm

Dave’s probably correct about the cause of the white. For giggles I tried to key your shot. I turned off “unpremultply result”(big improvement) checkbox, changed the screen gain to 89, screen balance to 51. In the Screen Matte settings I went with clip black to 41 and clip white to 80. Finally I chocked the shot using the Screen Shrink/Grow to -1.0

Here’s the result(some white left, but not as bad):

Johnny Cuevas, Editor
Thinkck.com

“I have not failed 700 times. I have succeeded in proving that those 700 ways will not work. When I have eliminated the ways that will not work, I will find the way that will work.”
—THOMAS EDISON on inventing the light bulb.
Dan Caz
May 25, 2012 at 5:14 pm

Thanks Dave

You’re absolutely right – the edges are the worst! The key looks much too smooth and fake by the time I’ve choked the life out of the edges just to clean them up.

I am really starting to understand the disadvantages of handycam “HD”. It looks fine to just play back but takes a major quality hit when editing. Now that I think of it, bad edges are my biggest problem every time I do green screen, now I know why. Gotta save up I guess.

Thanks again!

Dan Caz
Dan Caz
May 25, 2012 at 5:17 pm

Thanks for the help John

I wouldn’t have thought to uncheck that box because every tutorial I’ve ever seen on the subject either ignores it or says to keep it checked.

I’ll give those settings a try. Appreciate it!

Dan Caz

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