phg alpha chanel question

[zsurM]

Could you give an example what you're trying to use it for?

As far as I know, PNG does not support the extra bit channel for alpha channels. It does however support transperenices, like you said, which is best for web graphics and such.

[frankco]

Hi itsme,
Good question!

The official png home page says that they can, but it seems that Photoshop discards the alpha channel as soon as you save it as a png. Even Photoshop's help section says that pngs do not contain an alpha channel, at least in Photoshop. Perhaps you need another program or plug-in? If you look at the second link below there is a section "useful links" that has a plugin to enhance Photoshop's png cababilities.

Here's a link to the official png home page. Scroll down to the alph channel section. It clearly says pngs can have an alpha channel.
http://www.libpng.org/pub/png/pngintro.html

Here's a tutorial on pngs and photoshop. Maybe it will shed some light on it. It didn't for me but hey, you might figure it out. If you do let us know.

http://user.fundy.net/morris/redirect.html?photoshop27.shtml

Of course if I were you, I'd take zsurM's suggestion. He could probably help you out with what you are trying to do.

- - - - - - -
Okay, I had to edit this after reading user.fundy.net again.

Pngs can have "variable transparency, more commonly referred to as alpha transparency or translucency".

Also,
"Finally, with the release of Photoshop CS (version eight), Adobe addressed nearly all of the remaining PNG issues, however, support for alpha-indexed PNGs was not added. So, regardless of which version of Photoshop you use, you'll still need PNGQuart."

frankco

[itsmefool]

Cheers for the help I'll have a look at the links you sent me....


I've looked into it a little further and I cant believe I missed it to start with its sooo obvious {:-) and I cant believe how small a png file is compared to the PIM format I've been using.. Basically ive been using PIMS because the file size is nice and small compared to using TGA's (I work in the games industry if you're wondering why I'm so concerned with size - aint that always the way though LOL) Anyway the easiest way to get a PNG with a feathered alpha is to simply draw your image (Obviously not on the background layer - on a new layer) then just delete the background layer so you get the old checker pattern as your background then save your image - its that simple!! Of course it does mean that your alpha needs to be the same as your image but for what I need thats fine!!! and the file size is SOOOOOO SMALL {:-) Cheers for your help though {:-)

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