I have created multiple masks (4 layers) to reveal elements of one layer. I need to export with alpha channel and when I turned on the transparent background, ready for rendering, I noticed my masks were black. What do I need to do to make the masks output correctly?
Oh, I remember you -- you're the lady who had problems with Keylight in FCP. Hope the AE version was easier to figure out.
To make transparency, you first have to select a Quicktime codec that supports alpha channels. Select from ProRes 4444, PNG (the codec, not the image sequence), or Animation, in order of preference & availability.
Then, you need to add your comp with transparency to the AE Render Queue -- don't export! It's bad AE practice. Use the Make Movie command under the Composition heading.
In the Render Settings, select the proper field order for your footage, if you need to.
And here's the Big Kahuna -- the Output Module. Set it for one of the codecs mentioned above, Millions of Colors + (or trillions, perhaps), RGB + Alpha, and Straight. Don't use Premultiplied: FCP doesn't like it.
Then render, import into FCP, and use with satisfaction.
Sr. Promotion Producer
KCRG-TV (ABC) Cedar Rapids, IA
Actually ended up doing Keylight in FCP with one pass and lots of fine tuning, and with no masks. Adding a mask to inside well was crashing FCP continually or creating a grey silo. I believe the primary issue: if I had pure HD and not HDV my keying would have been easier and ultimately cleaner. My final is good though for what I will use it for.
I just figured out the alpha. I am referring to creating multiple masks using solid layers so I can target just one layer. My masks were showing black so I finally figured out its changing mode to Silhouette Alpha.