In article <41ebabb6@news.povray.org>, Warp <war### [at] tagpovrayorg> 
wrote:

>   There's no one single way of making lzw encoding (even though the result
> is decodable with any regular lzw decoder). Some programs do a better job
> than another. You should definitely not trust some random image editor to
> give you the best possible png compression ratio because they usually don't.

PNG is not LZW, it's the older LZ77 compression, which was unencumbered 
by patents when it was chosen. I was comparing LZ77 PNGs with LZW TIFFs. 
The TIFFs came out consistently smaller...not much, but not by an 
insignificant amount either.


>   Run the png through pngcrush and advpng and then compare it to the tiff.

I did use pngcrush, but not advpng. The PNG images were compressed about 
as well as is possible, the TIFF images were unoptimized.

-- 
Christopher James Huff <cja### [at] earthlinknet>
http://home.earthlink.net/~cjameshuff/
POV-Ray TAG: <chr### [at] tagpovrayorg>
http://tag.povray.org/

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