JPEG made its patent-free baseline mandatory — and became photography's format

In the late 1980s a photograph was a prisoner of whichever machine produced it: scanner vendors, software houses and equipment makers each shipped their own compression. The ISO/IEC and CCITT (today ITU-T) formed a joint group — the Joint Photographic Experts Group — to issue one standard both the computing and telecom worlds could adopt. W3C's graphics pages record the ISO standardisation in August 1990 and ITU published the same text as Recommendation T.81, still served from W3C's site today.

The committee's decisive design choice was what to make compulsory. Every implementation had to support the baseline: an 8-bit DCT scheme with Huffman coding, chosen because it was believed free of patent claims. Better-compressing options such as arithmetic coding carried patent risk, so they went into the optional annexes. 'For this reason,' W3C wrote, 'these optional features are never used on the Web' — the standard itself quarantined everything a lawyer could reach.

The Independent JPEG Group released a free, working reference implementation in October 1991, dropping the cost of adoption to a compile. Combined with the mandatory royalty-free core, that put the same decoder inside every browser, camera and printer: MDN's current format guide still lists image/jpeg as 'currently the most popular' still-image format, supported by every major browser. Even progressive JPEG, part of the original specification, only reached browsers around 1996 — core first, enhancements whenever the ecosystem follows.

The counterfactual is written in the same documents. JPEG 2000 and JPEG XL compress better, and neither has universal browser support; MDN tells developers to ship fallbacks. A codec's adoption was never decided by its quality curve but by whether the parts you must implement could be implemented without a licence — and JPEG's committee engineered that answer in advance.

Patent-free core mandatory; patented extras optional

A mandatory royalty-free baseline means no one can tax conforming implementations — following the standard immunised you against patent claims rather than exposing you to them.

Patented optional features stayed unimplemented, because shipping them meant patent risk; the standard's own structure turned patents into a quarantine zone instead of a tollbooth.

The free IJG reference implementation made adoption nearly free, so 1990s web authors and camera makers took the format without negotiation.

A joint ISO/CCITT seat meant the computing and telecom ecosystems bought one standard instead of shipping rival versions.

In a compatibility standard, what is mandatory beats what is technically best. A royalty-free compulsory core turned every device into a JPEG decoder; patented options never grew.

Baseline JPEG has now been the default language of digital photography for more than three decades. W3C's note that the patented optional features are 'never used on the Web' still stands on its site, and MDN's current guide lists JPEG as the most popular lossy still-image format with support in every major browser, while successors with better compression (JPEG 2000, JPEG XL) remain the ones needing fallbacks. The patent boundary the committee drew in 1990-1992 is still the line the industry lives along.