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mask layer for noise and grain effect

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Lisa Inserramask layer for noise and grain effect
by on Jul 31, 2012 at 9:54:02 pm

Can't get the masking layer to isolate a part of my source layer. I have a black and white ramp as my mask layer. White should translate as "no effect" according to Adobe help. Setting my ramp layer as the mask, I see no difference in the source layer's grain effect between the white and black areas of my masking layer using any of the masking modes.

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Kevin CampRe: mask layer for noise and grain effect
by on Jul 31, 2012 at 10:31:17 pm

are you using the add grain effect, and selecting the masking layer from within the blending settings? and, is the layer that you are selecting a solid with the ramp effect on it?

if so, then you need to pre-comp the solid with the ramp (choosing to move all attributes).

what's happening, is the add grain effect is looking at the solid prior to the ramp effect being applied, so the ramp is not being used by the add noise effect. this is common in most compound effects.

if you wanted to keep control of the ramp within the same comp, you can use this recipe:

  • add the ramp effect directly to the layer that will have the add grain effect.
  • then add the unmult effect (free download from red giant). this will key our the black.
  • add cc composite effect.
  • then add the add grain effect.
  • and last add another cc composite effect, setting the 'composite original' to behind and deselect the rgb only option.

Kevin Camp
Senior Designer

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Brian CharlesRe: mask layer for noise and grain effect
by on Aug 1, 2012 at 12:54:47 am

Which effect are you applying?

If you're using a layer with the Ramp effect applied as a control layer for an effect, you need to Pre-Compose the Ramp layer for the effect to "see" it. Otherwise it sees the layer without the effect applied.

This has to do with the After Effects Render Pipeline or Render Order. Since all compositing is the result of calculations, just as in math there is an order that operations are performed. To pass the Ramp pixels to the effect you need to pre-render the Ramp which is done by Pre-Composing.

Select the Ramp layer and from the Layer menu choose Pre-compose.

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Lisa InserraRe: mask layer for noise and grain effect
by on Aug 1, 2012 at 1:44:16 pm

Thanks Kevin and Brian. Of course, precompose worked like a charm. I put two and two together last night and realized this (sometimes you just have to get away from it!)
thanks again

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