View Full Version : PNG transparency

12-05-2002, 10:52 AM
Let's keep this to IE for arguments sake...

When I set the transparency on my png's background and then save it as 24 bit, the transparency doesn't show...rather a solid color. When I save the transparency as palette-based (256 colors or less), the transparency holds and is ok.

What's with that?

Any good tutorials on png and transparency around? Nothing heavy duty (partial or alpha) as I'm just interested in simply setting my bmp's background to transparent.

Thanks :D

Quiet Storm
12-05-2002, 10:04 PM
What graphics program are you using?

12-05-2002, 10:17 PM
Well, I'm using PSP but I heard PS does the same thing. You can't have a transparent background with more than 256 colors...There goes all my detail unless someone knows a remedy...:rolleyes:

Quiet Storm
12-05-2002, 10:59 PM
Form a quick search, it seem as it the transparency depends on browser settings...?

NOTE: All images with borders are alpha transparent PNGs. Internet Explorer and Netscape 4.x users will see different background colors in these images depending on their browser settings.

Users of browsers that support alpha transprent PNGs will see the same background color as the text areas of this page.

Are you doing "set and view palette transparency"? I know on my PSP7, if I 'set', but don't 'view' the transparency (when saving as .gif) it won't show up on the final image. I always have to view the transparency to save it as transparent...

Quiet Storm
12-05-2002, 11:04 PM
Found this:

12-06-2002, 05:23 AM
Well, high bit just isn't supported in IE yet...just low bit. There is a work around...and since I'm just using <input>, I suppose I could maybe use this in an external css class...dunno. Either that or adjust the backgrounds in high bit to match the page color. Thanks Mr Storm :rolleyes:

Workaround for IE (http://webfx.eae.net/dhtml/pngbehavior/pngbehavior.html)

Quiet Storm
12-06-2002, 04:02 PM
I played around with PSP7 last night...

I think it goes like this:

File > Export > (something) PNG.

There are a lot of controls to set up for PNG transparency... I didn't know exactly what I was doing, but there was an image that I got the transparency to stick (looked good, too!), but I'm not sure how I did it. There's 'Alpha' transparency - I think that was the one, but also 'Single Colour' transparency...

I'll try it again tonight and see if I can do it again. :)


12-06-2002, 11:41 PM
What about PNG transparency in photoshop? Can you have 256 colors with that? :confused:

12-06-2002, 11:56 PM
Yep...Using the alpha enables you to use high bit...The problem is, the major browser doesn't support the transparency yet.

Yep...You can use low bit 256 colors and the transparency works...Problem is, it's just a tad smaller than a gif and most definition is lost kinda defeating the whole purpose of png's high bit resolution.