Two alpha channels

Maybe this is old news to you, but I just realized that there are actually two alpha channels in FF, one is the selection, and the other one the transparency of the original. It has some interesting possibilities connected with it (And it only took me a year to realize this...).

Here comes the first example.

A rather plain-looking source image created in Photoshop, which consists of an image and two alpha channels:

RGB


Alpha#1 (for transparency)


Alpha#2 (for bump)


Step 1: Load Alpha#1 as a selection and run through "process transparency" filter.

Result looks pretty boring:



Despite all appearances, the color information is still there in the transparent areas. Now the fun starts.

Step 2: Load Alpha#2 as a selection and run through "Glass Ball" filter (new filter I just made), and, abracadabra:



The fascinating thing is that both the transparency and the bump map are there, neither were created in FF, both came from the original Photoshop file, from two different alpha channels.

(I better put together another example which would not be as easy to create in FF for the original so that you can really see what I think the "big deal" is...)

Here's a fancier example. The original images are made in Photoshop.

RGB:


Alpha#1 (Transparency):


Alpha#2 (Bump):


FF Result:



I renamed the filter "Spherica Custom Double-Alpha." The companion filter that does the first step is "Process Transparency Snippet." Coming up for submission.