As previously mentioned, expiring today is the patent on the LZW compression scheme which forms the basis of the GIF file format. Well, at least if you reside in the United States. Canadians, Europeans, and others are stuck with it for another year.
Kuro5hin has a great eulogy on the highs (and lows… mostly lows) of Unisys’ ownership of the format. From the creation of GIF87 in 1987 on, Unisys was content to sit back and let people use it. In 1994, I suppose their lawyers caught on. Any developer using the format was shocked to learn that, come Christmas of that year, we’d have to pony up a huge licensing fee just to include GIF importing and saving capabilities in our software.
I use the inclusive ‘we’ because I was writing a DOS–based image editor at the time, if you can believe it. I may even still have the Unisys licensing papers kicking around somewhere. I took one look at the $2000 initial license, considered I was writing shareware and lost all interest in GIF support.
So what does a public domain GIF (assuming that expired patents are released into the public domain — on this point I’m not clear) mean to the web developer? All praise of free data formats aside, not much. In this case, it means we don’t have to pay Unisys thousands of dollars per site we create.
Didn’t hear about that? At one point they were looking to bill any site owner using GIFs upwards of $5000US for a license. It was a big deal at the time. Hindsight says that would have been a great day for PNG had they gone ahead with the plan. It didn’t happen though.
So here we are today. GIF is 16 years old, while PNG is 8. They’re now both free file formats, which means the only reason to use one over the other is technological — Have another look at some of the technical issues involved in using PNG if you need a refresher.
Happy GIF Freedom Day. Ironically celebrated with a PNG banner, just cause I’m that kinda guy.