Alpha Transparency vs Index Transparency For 8-bit PNGs
The portable network graphic (PNG) is my favorite image format for the web. Its lossless compression can be beautiful for photographs with crisp details (although considerably larger than using jpeg compression), and it’s ability to pull double duty with an indexed color pallet make it super versatile. And of course there’s its ability to display graded transparency.
Its popularity has suffered for a long time, due to Microsoft’s decision to not correctly support the transparency feature in the true color versions of the format in their
That’s interesting news. I just found this site looking for some info on the difference between 8bit PNG transparency ( which I’m very familiar with ). But, I’m working on converting, or trying to convert the 8bit (256 color) graphics I have, too a 32bit png image. I’ve not worked much at all with 32bit PNG images.
I’m currently using Paint Shop Pro 7.04 and it allows me to save my PNG files with single color transparency, or Alpha channel transparency. I’m in 16 million color mode but there doesn’t seem to be an option for 32bit, it only supports (I assume) 24 bit images at 65k colors.
What’s the difference between 24bit alpha transparency, and 32bit RGB transparency in PNG’s? I only need the BG color as the transparent color and the rest of the colors in the image should stay opaque.
I would appreciate any feedback. Thanks!
Comment by Kevin Hansen — January 27, 2008 @ 12:52 pm