Photoshop Alphas

[user_deleted]

I have been getting myself completely confused lately over the correct way to create a still image in Photoshop with an alpha channel that i can open in Shake and overlay onto moving video.

I know i can import a .psd but i also know Shake isn't too happy with those and once rendered tend to look horrible. I have tried creating tiffs, tgas with alpha channels (are layer masks the same thing?) but when i bring them into Shake, there is no mask.

Please somebody, tell me the correct procedure in Photoshop to create a file i can bring into Shake and overlay?
and what is the prefered file format ?

thanks (eating vast quantities of humble pie!)

adam

edit -

further investigations revealed that the tif files did have the alpha masks and that all i needed to do was connect the fileout node to both sides of a switchmatte node and the problem was cured.

[user_deleted]

i personally avoid psd files at all cost since even if they seem convenient for some things they'll come and hunt you down with a bug in the worst moment.

as for tiffs, you need to make sure that your layer mask gets backed into a real channel. i usually just convert it into a selection (command-click), then switch to the channel tab andd hit the save selection as channel button.

++ christoph ++

[deke-kincaid]

What version of Photoshop are you using?

[user_deleted]

i'm using CS2.

The problem was two fold - i was making the alpha incorrectly (layer mask as opposed to alpha channel). Once i'd figured that bit out i realised that the tiff did have the alpha channels and all i needed to do was attach the file to both inputs on a switchmatte.

Now it works perfectly.

[user_deleted]

QUOTE(lightningad @ 12/07/06, 10:04 PM) [snapback]254330[/snapback]
...and all i needed to do was attach the file to both inputs on a switchmatte.

actually i suspect all you did is premultiply the image through the switchmatte. MMult would give you the same result.
++ christoph ++

[user_deleted]

When I bring in the RGBA image over to Shake from Photoshop, I FileOut it as the same format (RGBA)... then FileIn the updated image. Problem solved!

[user_deleted]

QUOTE(breno_speno @ 12/08/06, 06:30 PM) [snapback]254397[/snapback]
When I bring in the RGBA image over to Shake from Photoshop, I FileOut it as the same format (RGBA)... then FileIn the updated image. Problem solved!

i dont quite get it, why not save it in the right format in the first place?
no problem to solve.
++ c.

[user_deleted]

I find a problem with Photoshop to Shake. The alpha channel is offset, look fine in the viewer, when rendered to flipbook it looks wrong. With any file format. Saving it through Shake solves that problem for me.

[user_deleted]

QUOTE(breno_speno @ 12/11/06, 05:37 PM) [snapback]254605[/snapback]
I find a problem with Photoshop to Shake. The alpha channel is offset, look fine in the viewer, when rendered to flipbook it looks wrong. With any file format. Saving it through Shake solves that problem for me.

k, now i understand...
i just had a project where we used stills from photoshop generated tiff and havent seen the problem you mentioned (osx 10.4, shake 4.1, cs2, flattened tiff 8 and 16bit, IBM encoded).

will keep an eye open in the future though. anybody else had problems with flattned tiffs?
++ c