CG study (After Effects, Nuke, Maya...), English study and more.

Sunday, May 3, 2009

[After Effects]-Keying summary

Luminance keying
Similar to Level

Linear Color Key:
Isolate particular color,
Matching Softness will end up with setting closer to 1%
Double click layer to make you easier to add/subtract color

Using Keylight:

1.choose initial color
2.go Status
3.try Screen Balance at setting of 5, 50 and 95
4.boost Screen Gain if you need
5.set Despil Bias (select color which doesn't have spill)

duplicate the layer to make matte separated as Core and Edge

for Core (below)

1.twirl down the Screen Matte
2.adjust the Clip White value down until you start to see a matte that consists of entirely black pixels in the background, and turns the gray pixels in the edge green (od blue)
3.go back to RGB mode, adjust Grow/Shrink about to -3

tips for Keylight

edge looks ok, but you can see the noise---try Clip Roll back

"Screen Pre Blur"=does PRE blur
"Screen Softness"=adds softness AFTER keying
choose Corrected Source to create JUST RGB channel
blur particular channel (Blue channel contains noise more than Red or Green)
1.add Channel Combiner (RGB to YUV)
2.add Channel Blur (Blurriness about 1~2, tick Repeat Edge Pixels )
3.add Channel Combiner (YUV to RGB)
4.start keying

eye is far less sensitive to blue than green

Simple Choker works better then Matte Choker because softness control in Matte Choker sometimes creates bad key

use Spill Suppressor or Hue/Saturation to do spill suppression


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