Mixed transfer layers while preserving alpha
by Steve Green
on
Feb 11, 2009 at 8:15:43 pm
Hi,
I was trying to do something I thought would be simple lately, namely adding a bit of bloom to a layer, by blurring the highlights and adding to the existing layer.
The problem came when the layer had alpha, and clipped the bloom to the alpha rather than bleeding with the blur.
So I turned off alpha on the bloom layer but noticed this makes the whole comp opaque, even though the bloom layer is using transparency from being added - if that makes sense.
Re: Mixed transfer layers while preserving alpha by Eric Craft on Feb 17, 2009 at 10:50:29 pm
Instead of doubling the footage, add an Alpha Arithmetic with it set to Set and 100%. This will remove the alpha, now use the set matte linked back to the original footage. To combine to alpha channels use a Compound Alpha Arithmetic to combine the alphas using the transfer mode you desire, then use this in a set matte.
Toxik has options for how alphas are handled when combining 2 pieces of footage, but Combustion doesn't have any options for this so you must manually do it.
