Comments on: PNG-8 with alpha transparency http://edmondcho.com/2009/04/30/png-8-with-alpha-transparency/ 'nuff blah blah: mumblings, code and junk Tue, 24 Apr 2012 04:54:06 +0000 hourly 1 By: Jeff Harmon http://edmondcho.com/2009/04/30/png-8-with-alpha-transparency/comment-page-1/#comment-13337 Jeff Harmon Thu, 04 Jun 2009 17:22:25 +0000 http://edmondcho.com/blog/?p=164#comment-13337 Both in CS3 10.0.1 and CS4 11.0.1 I get the option of saving transparency with PNG-8. I am now officially confused... Yes, it is 1-bit transparency, but that makes sense, since it's a reduced bit-depth version of PNG. Oh wait, I see, Fireworks plays with the details of the spec better! http://www.sitepoint.com/blogs/2007/09/18/png8-the-clear-winner/ http://en.wikipedia.org/wiki/Portable_Network_Graphics#Ancillary_chunks (Sorry I was so reactive and misspoke about 2-bit vs. 1-bit; the only place where you were off is that PNG-8 does support 1-bit transparency in Photoshop) Both in CS3 10.0.1 and CS4 11.0.1 I get the option of saving transparency with PNG-8. I am now officially confused… Yes, it is 1-bit transparency, but that makes sense, since it's a reduced bit-depth version of PNG. Oh wait, I see, Fireworks plays with the details of the spec better!

http://www.sitepoint.com/blogs/2007/09/18/png8-the-clear-winner/

http://en.wikipedia.org/wiki/Portable_Network_Graphics#Ancillary_chunks

(Sorry I was so reactive and misspoke about 2-bit vs. 1-bit; the only place where you were off is that PNG-8 does support 1-bit transparency in Photoshop)

]]> By: Edmond Cho http://edmondcho.com/2009/04/30/png-8-with-alpha-transparency/comment-page-1/#comment-13336 Edmond Cho Wed, 03 Jun 2009 14:31:58 +0000 http://edmondcho.com/blog/?p=164#comment-13336 Hey Jeff, That is actually where I learned this from. I had credited brenelz at the end of my post. Hope this is fixed in CS4... Hey Jeff,

That is actually where I learned this from. I had credited brenelz at the end of my post.

Hope this is fixed in CS4…

]]> By: Jeff Harmon http://edmondcho.com/2009/04/30/png-8-with-alpha-transparency/comment-page-1/#comment-13335 Jeff Harmon Wed, 03 Jun 2009 06:33:04 +0000 http://edmondcho.com/blog/?p=164#comment-13335 I was wrong. Photoshop doesn't permit PNG-8 to have a 2-bit channel as it should, at least in CS3. Not sure if they fixed it in CS4. Interesting post here: http://www.brenelz.com/blog/2009/01/27/png-8-alpha-transparency-screencast/ I was wrong. Photoshop doesn't permit PNG-8 to have a 2-bit channel as it should, at least in CS3. Not sure if they fixed it in CS4.

Interesting post here:

http://www.brenelz.com/blog/2009/01/27/png-8-alpha-transparency-screencast/

]]> By: Jeff Harmon http://edmondcho.com/2009/04/30/png-8-with-alpha-transparency/comment-page-1/#comment-13334 Jeff Harmon Wed, 03 Jun 2009 00:37:27 +0000 http://edmondcho.com/blog/?p=164#comment-13334 PS, Photoshop handles all of this perfectly. PS, Photoshop handles all of this perfectly.

]]> By: Jeff Harmon http://edmondcho.com/2009/04/30/png-8-with-alpha-transparency/comment-page-1/#comment-13333 Jeff Harmon Wed, 03 Jun 2009 00:36:52 +0000 http://edmondcho.com/blog/?p=164#comment-13333 PNG-8 permits only a 2-bit transparency channel, meaning either it's transparent or opaque, period. PNG-24 permits an 8-bit transparency channel, with smooth gradients. They are not equivalent, and PNG-8 will only have positive visual results with sharp edges. PNG-8 permits only a 2-bit transparency channel, meaning either it's transparent or opaque, period. PNG-24 permits an 8-bit transparency channel, with smooth gradients. They are not equivalent, and PNG-8 will only have positive visual results with sharp edges.

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