Adobe After Effects Chroma Keying (Page 1) - Post-Production - Forums

1 Topic by Generalaustin March 27, 2012 (10:07pm)

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Topic: Adobe After Effects Chroma Keying

Ok here is the deal... I have adobe after effects cs whatever the newest one. Anyhow so I have a couple videos that I got from you tube with explosion or muzzle flashes on a black background *not green* Now... I also have ones on green that i can nicely take out the green using Key Light. But I cant do that if it's on a black background. Why is this? I can easily make the back transparent if it's green or blue but when it's black it wont do it. Anyone know why? Anyone know another way of getting around this? Anyone know what the heck im talking about? =P

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2 Reply by Lechnology March 27, 2012 (10:52pm)

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Re: Adobe After Effects Chroma Keying

Not an answer to why Keylight doesn't key out black but: change the blending mode. No need for keying.

Example

Note: it does not look better just by keying out a color. It looks out of place and doesn't blend well with the main footage. You have to take advantage of the blending modes.

0:37 and 1:00

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3 Reply by doctormedoctoryou April 2, 2012 (01:00am)

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Re: Adobe After Effects Chroma Keying

Keylight is designed to remove specific colour values, whereas Black is not a colour.

As suggested, use the layer blending modes to remove the black - I'm not sat in front of After Effects right now, but i think Screen or Overlay are the ones that you need. They will make the black pixels magically vanish!

There are other ways to do this that are more involved, and require the use of Luma keying (ie - Luma = brightness), then removing edge matting....yadda yadda..so many ways!

"Silly Keeps You Sane!"

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4 Reply by AngryChair April 2, 2012 (04:14am)

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Re: Adobe After Effects Chroma Keying

As the good Doctor said if you change the blend mode to Screen it will take out the Black background. If you choose Add it should also put some nice extra glow onto your muzzle flash which will really make it pop.

Hope that helps