So long...


...and good riddance. United States Patent No. 4,558,302 expires today. Better known as the LZW patent. This is the technology behind the common GIF file.

As of the 21st, U.S. companies and organizations that produce software and hardware products that use the GIF format (and other LZW-related technologies) will no longer be required to pay license fees to Unisys for doing so. However, LZW patents are still in effect for Canada (until July 7, 2004), the UK, France, Germany (expiring June 18, 2004) and Japan (expires June 20, 2004).

Will the expiration of this patent be the death knell for PNG? I don't think so. PNG is still the graphic format we should be using (although it currently doesn't support animation like GIF does -- MNG is the answer for that). But the quality is superior and offers transparency. Sadly, it's not as widely supported as GIF (talking about you, Internet Explorer).

See Also


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» GIF Freedom from LibraryPlanet.com
“So long and good riddance. United States Patent No. 4,558,302 expires today. Better known as the LZW patent. This is... [Read More]

» PNGed off with PNG text from Tom Gilder's Blog
Lots of people have been heralding the expiration of Unisys's GIF patent today (OK, well, actually yesterday in my time zone). Of course, everyone is also mentioning how great a format PNG is (which, indeed, it is). When I... [Read More]

» Goodbye GIF from Web Design/HTML
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» Free GIFs, Skippy! from ***Dave Does the Blog
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Mark said:

Actually, you might be talking about Mozilla soon too.


Joel Spolsky said:

Yeah, it doesn't help, unless for some strange reason your software is only sold in the United States. Unisys has made it clear they're not letting people write GIFs without a license until ALL the patents expire, unless you can somehow prove to them that your software will never be exported.

Jeff said:

For the American software developers, it seems to me that if Unisys wants to enforce, for example, a German patent on an American citizen, they would have to file a lawsuit in a German court. A US court isn't going to take a case about a German patent. And I'd be curious if Germany would even allow an American company to sue an American citizen in their courts. I'd also be curious if the countries where the patents are still valid have even had any software patent infringement suits. If not, I think Unisys would be taking a risk by suing in court in the event they lose and set a precident. That would, for all practical purposes, void their patent in that country. Interesting...

Jeremy Wood said:

As a developer I've received a lot of emails from enthusiastic users pointing out that the GIF patent is expired.

To add to what Joel said:
A lot of software out there today is distributed online. The internet is international, so I really am breaking international patent laws by posting gif software online.

Regarding Jeff's comment:
I agree it *should* be OK. But a lawsuit with UNISYS -- even if I'm in the right -- is not something I'm willing to risk. We've waited, what, 8 years for the American patent to expire. One more year and all the international ones will have, too.

UNISYS's official (but "subject to changed") statement is here:

I've written a condensed history here:


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