[Courses] [gimp] Tux images

[Travis Casey]

On Saturday 19 February 2005 21:27, Kenneth Gonsalves wrote:
> On Sunday 20 Feb 2005 5:25 am, Mary wrote:

> > For importing images I'd suggest finding a PNG or GIF image of the
> > right
>
> heard somewhere that GIF is to be avoided for copyright reasons?

The LZW compression algorithm used in GIF files was patented.  The 
developers of GIF got the algorithm out of a magazine, and didn't know it 
was patented.

Unisys, the holder of the patent, didn't do anything about it until 1994, 
until they decided that anyone making software that created or read the GIF 
format should have to license their patent.

It no longer matters now.  The patent has expired in the US, Europe, Canada, 
and Japan, which as far as I know is everywhere that Unisys bothered to 
patent it.  The algorithm is now public domain, and no one has to license 
it from Unisys.

Still, though, the patent didn't expire in the US until 2003, and ran 
through June of 2004 in Europe, Canada, and Japan.

The Unix "compress" program ran into the same problem, as it also used LZW 
compression (and there as well, the creator got it from a published 
article, and had no idea it was patented).  

For end users, it was never a problem, since Unisys never asked end users of 
software to license their patent -- only programmers creating software to 
read/write GIFs.  And now it's no longer a problem for them.

For more history, see:

http://www.kuro5hin.org/story/2003/6/19/35919/4079

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       |\      _,,,---,,_     Travis S. Casey  <efindel at earthlink.net>
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