[Heather Crank] “So I created an alpha only channel, an rbg straight alpha channel and tried using a luma matte for the matte wipe..but the transition now has a light white edge to the right of the transition/image edge… because I can’t see the end result, I can’t tell if it’s working until it comes back to me.”
Here’s how you can simulate FCP’s Alpha Transition:

Clip Alpha Matte is a luma matte for Clip, and Wipe Matte is a luma matte for FCP Clip A as it transitions into FCP Clip B. (I split Clip A in the attached AE screenshot at the start of the transition to make it easier to use the luma matte.)
For a smooth transition, the Clip Alpha Matte should start and end in full black. The Wipe Matte should start in full white and end in full black. Grays in between will control the opacity of the clip and the transition from A to B, respectively.
Walter Soyka
Principal & Designer at Keen Live
Motion Graphics, Widescreen Events, Presentation Design, and Consulting
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