alphA channels?

[Tim Kurkoski]

If you’re using a PSD file, just make sure that your background is transparent in Photoshop. That is, make sure you don’t have a Background layer. (If you do, double-click on it, click OK, then delete it.) As long as the transparency checkerboard is showing through, AE will read the alpha channel automatically.

If that’s not working, you may need to tweak the alpha settings for the file in AE through the Interpret Footage dialog box.

[Andrew Potter]

Thank you for your reply.
Hmmmmmm.
This is just as I have done. Only transparent background in psd file.
psd is a single, named layer. Have ‘interpreted footage’ as straight, ignored, and reverse alpha.
When imported into AE, sometimes it comes with a black background, sometimes white.
Is it possibly an old app issue? (photoshop 7.0; AE 5.5)

[Tim Kurkoski]

Well, I cranked open PS7 and AE5.5 just to check. No problems for me.

When does it come in white, and when does it come in black? Are you changing any settings?

When you import the image, you should get an option to choose which layer(s) you want, or if you want merged layers. Either option should work.

Are you defining an extra alpha channel in Channels palette in Photoshop? That could throw it off. That’s definitely not something you need to do for AE.

[Andrew Potter]

It comes up white with ‘interpret footage’ as alpha ignored
Interpret footage as ‘straight’ give me a black backgrpond.
A direct import w/o interpret footage gives me a black background.
Is my AE composition set up wrong? Is there a setting for a transparent background in AE like there is
in photoshop?

[Andrew Potter]

Also; not sure what you mean by ‘defining extra alpha channel”
There was an alpha channel in Channels palette. I deleted it, and it made no difference.

[Tim Kurkoski]

Yes, that was an extra channel.

Try a simple test. Create a new Photoshop file with a transparent background. Throw on some text or a brush stroke. Just something simple. Make sure it’s a bright color (not black), just to make sure it shows up easily in AE.

Import the file into AE, make a new comp, drop it in.

If that much is still failing, there’s probably something wrong with AE. Try dumping the prefs file. Might also want to dump the Photoshop prefs and re-trying the test procedure, just to make sure Photoshop isn’t doing something weird with the save.

[Andrew Potter]

OK, that works fine.
Now, when I import it into fcp, I lose the tranparency,
and it brings in the entire composition size background.
Again, I’m trying to create a simple animation in AE, (a still image imported from PS, with a few size adjustments to simulate motion)
Now, when I render and import .mov into fcp,
it brings the entire 640 *480 (or whatever) screen size with it, with a white background.
I just want my simple little animation composited against a video background.
Maybe I’m rendering it wrong??
Thanks for your continued troubleshooting.
-ap

[Tim Kurkoski]

Yes, make sure you’re selecting the RGB+Alpha option in the Output Module settings when you render from AE. Your codec also needs to support alpha channels (the Animation codec, for example).

I’m not familiar with FCP, so I can’t comment on how it interprets transparency data in a PSD file. You might have to make an explicit alpha channel, rather than relying on FCP to interpret the transparency data of each separate layer, like AE does.

[Andrew Potter]

Presto! Yes, output wirh RGB + Alpha does it!
Thank you very much!
-ap