Masking question

[Tommy L]

Aftereffects 6.5pro question:

I would like to use a layer to selectively bloom the bright areas of the layer below. I have tried the following, but think i have missed something.

Compound Bur bottom layer. In the compound blur, select top layer as 'blur layer'. Desaturate top layer. change levels so the bright areas are real bright, all else black.

 

It just blurs everything. Any advice?

[Nils Norgren]

Filters like compound blur use a layer Before any effects are applied. Your bottom layer is using the other layer before the levels are applied, you need to pre-compose the layer for it to work.

 

My solution for blooms are to use adjustment layers, if you make an adjustment layer with a levels or preferably a curves, set the darks to crush to black, and pin the highlights with some areas going to pure white, then use a fast blur to blur the layer (some would add a gamma before and after the blur to get a photographic blur) and then set the adjustment layer to the "Add" mode, then use the transparency of the layer to increase/decrease the effect. You often will want to couple this with an overall shift in the mid tones to push the image down so that the blooms will not blow the image out.

 

Adjustment layers in after effects can also use a soft mask to isolate where they affect; this is great for vignetting.

 

Hope things work for you.

 

-Nils