View Full Version : Has photoshop forgotten PNGs are 32-bit?

10 October 2003, 10:50 PM
I've been using Photoshop for YEARS. I'm running 7 now, have been for quite a while now, and it's behaved quite well. Recently (as in the last couple of days) I noticed that the PNGs it saves no longer allow for alpha channels. Uh I kinda need those to work. Heh.

I'm not sure what I could have done to kill them, so I was wondering if anybody knew what to check for? Is there a set of circumstances where even if you have an alpha channel, PS'll refuse to save a 32-bit PNG file?

10 October 2003, 11:06 PM
Well, I may have partially solved the problem. You know how Photoshop likes to deal with transparent PNGs by just blowing away the information in the base layer? Well, when I recreated that by jumping through a few hoops, it worked.

I'm reasonably certain I've created PNG files with Photoshop 7 where if I just saved the selection, it'd be an alpha channel. That no longer seems to be the case... Grr.

Any clues? I did recently reinstall Photoshop...

Ian Jones
10 October 2003, 01:38 AM
Check out the save for web feature. Make your background transparent. In the save for web select png-24 and then tick the transparency checkbox. My guess is that it just calls it 24-bit plus and alpha channel instead of 32bit for some silly reason.

10 October 2003, 04:26 AM
I remember back in school using 5.5 it would open the PNG's with the alpha channel. Now in 6 & 7 it opens them without the alpha channel..... rather it opens them up with a transparent background to begin with. I don't know why:shrug:

If you need to save an alpha channel, try saving it as a TIFF or TGA it will save the channels for you.

10 October 2003, 04:33 AM
*grumble grumble*

I hope Adobe realizes that they've created a huge problem here. You lose all the information you had outside of the alpha channel. :banghead:

10 October 2003, 03:14 PM
There were major alpha differences between gimp & photoshop I remember that. Gave one hell of a problem.

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