Alpha channel problem ... I guess

Posted by harry323 
Alpha channel problem ... I guess
November 18, 2010 02:52PM
I have a photograph of a grasshopper against a black background.

I have to matte this into a plate shot of a table.

I guess I need to fix the Alpha channel so that the black will disappear and the grasshopper will sit on the table.

I read that, in order to create a proper Alpha channel, I should export my grasshopper picture (unrendered) using the ANIMATION codec.

But when I do that I am still unable to make the black areas of the grasshopper shot transparent.

Can anyone point me in the right direction?

I have, of course, messed endlessly with the settings under Composite Mode and Alpha.

Thanks.

Harry.
Re: Alpha channel problem ... I guess
November 18, 2010 03:05PM
What kind of file is the grasshopper? (png,obj,mov)

""" What you do with what you have, is more important than what you could do, with what you don't have."

> > > Knowledge + Action = Wisdom - J. Corbett 1992
""""
Re: Alpha channel problem ... I guess
November 18, 2010 03:10PM
Harry do you have Photoshop?

If not send me the picture and I'll cut the little critter out for you.

You CAN use the luma or colour key and/or matte it out in FCP or Motion but its a lot of faff and I can probably do it in a couple of minutes so if you get it to me ASAP I'll send it back before bed.



For instant answers to more than one hundred common FCP questions, check out the LAFCPUG FAQ Wiki here : [www.lafcpug.org]
Re: Alpha channel problem ... I guess
November 18, 2010 03:27PM
Thanks for the reply - it's a JPEG.

Ideally I'd like to be able to use my new CHV KeyPro and set the "dropper" to black - I've tried that and can't get anywhere. I think I'll email Christophe.

H.
Re: Alpha channel problem ... I guess
November 18, 2010 03:33PM
Photoshop or Photoshop Elements. You have to have one. Easy to take out the black there and save the file with transparency.

All the best,

Tom
Re: Alpha channel problem ... I guess
November 18, 2010 03:41PM
To clear up the misunderstanding about the Animation codec, that really has nothing to do with what you want to do.
The confusion stems from Animation codec for a long time being the best codec for exporting video with an alpha channel out of FCP.
Now you can also do it with ProRes4444 too.

ak
Sleeplings, AWAKE!
Re: Alpha channel problem ... I guess
November 18, 2010 03:43PM
If you want to do it yourself in Photoshop follow one of these tutes:

[www.photoshopcafe.com]

[www.blog.spoongraphics.co.uk]

[www.graphic-design-employment.com]


Photoshop (and/or After Effects) should be classed as an essential App to have on ANY edit system without it you are going to waste time when something like this can be done to a fantastic quality in moments.

If you want to do it in FCP:

You should be able to do it in KeyPro but try the luma key instead along with the Matte Choker and Mask Feather to tweak the edge. But you'll probably also need to crop and/or matte out parts.



For instant answers to more than one hundred common FCP questions, check out the LAFCPUG FAQ Wiki here : [www.lafcpug.org]
Re: Alpha channel problem ... I guess
November 18, 2010 04:01PM
You also do not need to export your still as anything - just put it into the timeline and use the Filters.

However - I can pretty much guarantee you won't get the best edge with any FCP keying/matting.

You may want to take it into Motion if you don't have PS and use the Mask Tool (or Bezier Mask Tool)

[documentation.apple.com]



For instant answers to more than one hundred common FCP questions, check out the LAFCPUG FAQ Wiki here : [www.lafcpug.org]
Re: Alpha channel problem ... I guess
November 18, 2010 08:29PM
Thanks to Tom, Andrew and Ben for the advice and taking the time to answer in the first place.

Harry The Idiot.
Re: Alpha channel problem ... I guess
November 18, 2010 08:34PM
Oh - and by the way, Christoph Vorheim (he of CHV / KeyPro) has been immensely responsive to my idiotic questions after purchasing KeyPro ... so I'd just like to give his company a plug here if that's ok.

Best

Harry.
Re: Alpha channel problem ... I guess
November 18, 2010 08:38PM
Ben --

Is that a glass of Guinness in your hand? Looks like a half pint of the sacred fluid to me.

Ex-pat Brits like me need to know.

H.
Re: Alpha channel problem ... I guess
November 18, 2010 08:39PM
Christoph is one of the best and CHV plugins are awesome. Christoph helped imensily in re-doing this forum too.

Michael Horton
-------------------
Re: Alpha channel problem ... I guess
November 18, 2010 09:07PM
Yay Christoph!

And, since Michael implies that I can recommend Christoph's creations, I also own his REPAIR COLLECTION and his TEXT COLLECTION which I have been using for years.

Enough Christoph.

Best

Harry.
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