PNG is back!

Jokes aside, this is exciting news. PNG is back to its former glory after its progress stalled for over two decades. Did you know the U.S. Library of Congress, Library and Archives Canada, and the National Archives of Australia recommend PNG? It is important that we keep PNG current and competitive. After 20 years of stagnation, PNG is back with renewed vigor!

What's new?

• Proper HDR support (future‐proof, too!)

  Figure 1 shows the colors our eyes can see.
  The smaller, inner triangle represents the color space of most images.
  The larger, outer triangle represents the colors that are typical with a High Dynamic Range (HDR) image.

  This new HDR support uses only 4 bytes (plus the usual PNG chunk overhead).

  Chris Lilley—one of PNG's original co‐authors and current Technical Director contributing to the new PNG work—wrote an excellent article explaining how this works.

• Finally recognizes APNGs (animations!)

  Animated PNGs were proposed by Mozilla quite some time ago. Support was added to Firefox, but other programs hesitated to adopt them.

  Today, animated PNGs are widely supported. It is time for the spec to reflect reality.

• Officially supports Exif data

  Exif stores additional information such as copyright information and even camera lens and GPS location of a photograph.

• General tidying up—fixing errata, clarifications, etc.

Background

The last PNG spec was released over 20 years ago. Technology has advanced a lot since then. We're talking 3.5 years before the first iPhone.

In fact, technological advancement is what resurrected PNG. The W3C Timed Text Working Group (think: subtitles) needed HDR support in PNG. A proposal was made, but a few experts decided we could do better.

Momentum built, and additional parties became interested. Before we knew it, we had representation from (in alphabetical order) Adobe, Apple, BBC, Comcast / NBCUniversal, Google, MovieLabs, and of course W3C, who maintains the spec. It's quite the dream team.

With these titans behind it, the image format is back with full momentum. Work has already begun on the next two PNG spec updates.

Already supported

Many of the programs you use already support the new PNG spec: Chrome, Safari, Firefox, iOS/macOS, Photoshop, DaVinci Resolve, Avid Media Composer...

Plus, you saw some broadcast companies in that list above. Behind the scenes, hardware and tooling are being updated to support the new PNG spec. The next time you see a news ticker scrolling Brave dog saves family or the score banner update as your team pulls out a clutch play, check if it is HDR.

What's next?

I know you all immediately wondered, better compression?. We're already working on that. And parallel encoding/decoding, too! Just like this update, we want to make sure we do it right.

We expect the next PNG update (Fourth Edition) to be short. It will improve HDR & Standard Dynamic Range (SDR) interoperability. While we work on that, we'll be researching compression updates for PNG Fifth Edition.

Thanks

The PNG Working Group participants made all of this a reality. Be sure to let them know how much you appreciate their hard work.