Preview Alpha channel?

[stylewalker]

Im workin with tv graphics and we use alpha channels in the broadcasts. Is there any plugin know that can preview the Alpha channels effect straight in PS? As for now, i can only watch the alpha channel and guess how it will be or send it to the tv output to see the result.

[Scott W.]

if you turn on it's visibility in the channels palette you'll get a red overlay where the alpha channel masks.

Welcome to PST stylewalker.

[stylewalker]

Glad to be here!

I know i can preview the mask with the red overlay, but what i want is to really see how its gonna look when i send it throught the mixer to the tv.

[Metryq]

I've heard that some video cards support alpha channels, but I have yet to meet one. Likewise, there are some apps that can work with such cards. In short, you'd be able to view character generator-like keying realtime. I've always meant to look into this, but it's pretty far down on my priority list.

For now, you can use Photoshop's Video Preview function, which will show you the entire graphic, sans keying. (If you have an earlier version of Photoshop, look up Synthetic Aperture's Echo Fire plugin.)

[Kevin Connery]

You could add a layer mask to the image, and load the alpha channel to it. That would let the transparency take effect.

I'm not familiar with TV alphas, so this might not be what you're looking for--and you'd probably have to disable it/delete it before exporting it, but it might give you what you want.

[lokki]

hmm... just throwing out an idea here, 'cause I don't know if it would really work...

Flash 8 Pro takes advantage of live effects, including Alpha channels in video. Maybe that could work as an intermediary application? Also, with Flash's vector tools, you should be able to do some manipulation of the mask as well.

[sPECtre]

Why don't you put the image on top of another, Ps should respect the alpha (or just select the alpha, load as layer mask and you're done, as Sir Kevin pointed it out)

To continue on Metryq's post, in the preferences (Ctrl/command+K) in the transparency and gamut tab, you'l find a checkbox for "use video alpha"