Back in the old days, InfiniD had a neat little feature that when you rendered an alpha channel it was very easy to use it for compositing images in Photoshop. If you had something that was semi transparent , it would create shades of gray to be able to select transparency fairly easily and strait forward.

Now with Carrara, if I render using G-Buffers (alfa channels), it gives me some pretty confusing output. I am sure if I use "Channel Calculations" in Photoshop, I could probably use this output to achieve my purpose. I guess my question is. Where can I find a tutorial or does anyone have some insight as to how to use these strange alpha channels?

perhaps they could better assist ya if ya posted said image.
I don't actually know if any of the g-buffers can access the alpha map info in a particular
shader tree.

What are the g-buffers for? How do you use them? Are they only to be able to preselect parts of your image for color and exposure settings? Are they not meant for aiding compositing with an image editor?

I just confused as to what their purpose is, and how to take advantage of this purpose.

 The premultiplied alpha does what your asking regarding levels of transparency. The other G Buffers can be used in either Photoshop or video editing applications for a whole host of possibilities. 

Mark

G-Buffers are covered on page 668 of the new 6.1 Hel p manual.

 Thanks guys!