Another Photoshop Alpha Channel question

[mrpc]

Once again the online help of Photoshop 4 has left me frustrated.

I would like to create a black mask to overlay on a video clip using Photoshop. I'm using Premiere 5.1c with an RT2K and can't use the Clip filter because I also need to move and zoom the video clip.

Because I seem to be a low grade moron could you please post the response as a series of steps?

Create - new - blah blah blah

Evidently I'm doing something wrong with the alpha channel creation because when I do save copy as TGA file (and I can see the "Don't include alpha channel" check box) and then import to Premiere on an overlay track using alpha channel transparency it still masks the entire image.

Sigh.

Please halp!

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Abit BH6; 300A@450; 128MB
FastTrack66 dual KA 18GB & dual Maxtor 27G 6800; Marvel 200; MX300

[fluggo99]

Well, Premiere I can't help with (my company's a little slow on their purchases), but Photoshop I might. Assuming that you need the mask to be static, and assuming you can get Premiere to accept your mask, here's how to create it in Photoshop:

1. Go to File->New..., enter the appropriate dimensions, and make the contents "Transparent." Click OK.

2. Use your favorite selection tool (like the rectangular marquee) to select the area you want to be the hole.

3. Select->Inverse.

4. Use Edit->Fill..., and choose "Black" as the contents. Click OK.

5. Without changing a thing, switch over to the Channels palette and hit the <img border="0" src="http://www.fluggo.com/images/photoshop_mask.gif" align="center"> button to create an alpha channel.

6. Choose File->Save a Copy..., save as Targa, 32-bit.

Tadaa!

[robmcl]

I've been using PS for all my alpha channel work for quite a while. I've also read replies from a lot of other users, and it seem the basic difference I have is that I *don't* actually create an alpha channel in my PS files. I simply start my *new* file with a transparent background, and place/insert the actual .PSD file on the overlay track an apply the alpha option.
I can understand that if you're saving files in TGA etc format, that you may need to create that distinct alpha channel, but for me, the .PSD is easier. (I do a lot of titles etc as PS files and they *overlay* wonderfully.
HTH....Rob

[fluggo99]

(scratch head) Oh, yeah. Forgot all the Adobe products talk to each other. Dur!

[mrpc]

Gentlemen I thank you both for your replies.

I wanted the TGA since it is supported in realtime; I have gotten the PSD files to work in the past also, but they do require render time.

I'm going to fool around with both and see which is quicker (hopefully TGA) to render and then practice some more with PS. I tried your method last night Fluggo and had to go to Chroma Keying to get it to work so I'm doing something wrong. If only PS had someting easier like designating a Layer as alpha- I dont' really understand the channels and how they apply to layers and how to make the alpha selection show up to double check it.

Sigh.

Feel like I'm learning DOS 2 all over again.

Richard

[fluggo99]

<img border="0" src="http://www.fluggo.com/images/maskinpremiere.gif" align="right" width="192" height="170">I decided to go ahead and download the tryout for Premiere and see if I can't get my own mask working. Lo and behold, after playing around with a few settings, it looked like the picture at right. The key type is "Alpha Channel," but in order to see it, you have to press that button that looks like a page curl, just below the preview picture. My mask.tga is on Video 2, the underlying clip on Video 1A.

[robmcl]

Apologies all 'round.
Sorry fluggo (Forgot all the Adobe products talk to each other). I was actually addressing the PS issue and should have mentioned that I don't use Premiere either. I've only every used MediaStudioPro.
Sorry mrpc. Didn't read close enough to catch that you're running an RT2K. I have a lowly G200, so *everything* req's rendering <sheepish grin>

[mrpc]

Lowly my backside...I started with a Marvel and made a few training videos for work. Everyone liked em and so they gave me a (small) budget to boost quality.

Now I have a GL-1 with balanced mics, a portable Arri light set, RT2K, and a PIII-650 with 170GB of disk space.

The marvel does a wonderful job even tho it's analog. It's more what's behind the camera than whats in it I find.

Thanks everyone now I have more stuff to learn. (yippppeee)

Richard

[mrpc]

In other words....I just got really lucky!

R

[Scott Porter]

My problem seems to be related to your discussion . Maybe you guys can help. I am working with stills in Photoshop 6.0 converting the files to a format that is compatible with my Matrox LX Max Video Realtime Card which is driving Adobe Premiere 6.0. In order to get realtime effcts the card requires Targa files, 32 bit, each with an alpha channel added. I did all that and the stills came up fine for dissolves and tranparency on Video 2 and above tracks, but I could nt get the stills to key with each other like i could with avi video files. All I get is the effect of one still over a black background instaed of over the other still like it should. I had someone with photoshop 7.0 look at my Targa files to see if he could find any problems with them. When he saved the file the only difference between my 6.0 version and his 7.0 version was that his alpha channel showed up as a white box instead as a black box. He also found that the white alpha channels worked and keyed properly on his system, but my black alpha channels gave him the same problem even on his system. My question is: Whats this " white" channel showing up in Photoshop 7.0 and how do I get 6.0 to do it for me?