PNG's alpha channel in dim3 - Printable Version
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PNG's alpha channel in dim3 - ggadwa - Feb 16, 2003 04:25 PM
Probably somebody here has an answer to this.
I converted dim3 (in the current unreleased version) to use 32-bit PNGs. There is no more "blue screening" (old 24-bit dim3 art used pure blue as a alpha=0 color). Now you should be able to have any type of alpha.
My problem: I have NO idea how to edit the alpha! I'm this close to wasting time and making a program to convert blue -> alpha=0 and resave, but that doesn't gain me anything new.
Is there anything that handles this well? GIMP? I haven't d/l it (or X11) but I will if it works well for that.
PNG's alpha channel in dim3 - OneSadCookie - Feb 16, 2003 05:25 PM
GraphicConverter lets you edit the alpha as a grayscale image.
PNG's alpha channel in dim3 - jamie - Feb 16, 2003 07:20 PM
photoshop lets you build/edit one as a 4th channel in an RGB image also I believe.
PNG's alpha channel in dim3 - ggadwa - Feb 16, 2003 09:47 PM
Quote:Originally posted by OneSadCookie
I d/l GraphicConverter ... nice program.
I still don't get it, though I'll check the online docs. I can "show alpha channel" but I'm not quite sure what's going on. If that's an actual gray-scale representation of the alpha channel, and can't seem to work with it.
I'll figure this out yet. If anybody would like to post a quick tutorial, I'd be happy to read it.
For instance, if I had an image that had pure blue in it (0x000000FF), and I wanted to make that the alpha channel (i.e., cut out things that are blue.) I could select it, copy it to the alpha mask? That doesn't seem to work, but then again, I'm out of my area when it comes to art ...
PNG's alpha channel in dim3 - OneSadCookie - Feb 16, 2003 10:35 PM
I just remembered, GraphicConverter is buggy in 10.2.4. That probably makes it a not-so-good tool for trying to do this
PNG's alpha channel in dim3 - acedia - Feb 17, 2003 03:05 PM
In Photoshop, this would be easy - in fact, I think you could probably batch-process all your files at once.
However, using Graphic Converter (4.2), I think I figured out a way as well.
Select 'effect' menu => 'Add alpha/mask channel'
Then choose the magic wand tool (sorta looks like a little sparkler - on my palette, it's the second one down on the right.) and use it to select the blue pixels - whatever you want to be masked out (shift-select additional areas).
Once everything you want is selected, choose 'edit' menu => 'copy'
Select 'effect' menu => 'show alpha/mask channel'
Select 'edit' menu => 'paste at position' (0,0)
Now the only problem now is that the blue doesn't quite come out as true black in a greyscale channel, and only black is completely transparent, so:
Select 'picture' menu => 'levels,' to change the black and white levels, or it might be easier to select 'picture' menu => 'contrast' and increase the contrast as high as possible.
Then 'save as...' png.
This isn't a program I use much, so it might not be the most direct way to do it? Seems to work, though.