PNG 3.0 Now Supports Native Animation and HDR

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Quick Report

The W3C has officially released the PNG 3.0 specification, marking a significant update to the popular image format. The new specification formally incorporates native animation support and adds High Dynamic Range (HDR) capabilities, bringing the format in line with modern display technologies and industry practices that have evolved since the previous version was released in 2003.

  • Native Animation Support: The APNG (Animated PNG) format, which has been widely supported in browsers but was previously unofficial, is now officially part of the PNG specification
  • HDR Image Support: PNG 3.0 can now properly represent High Dynamic Range content with the addition of the new cICP, mDCV, and cLLI chunks
  • Wide Color Gamut: Support for advanced color spaces including BT.2100 PQ/HLG and Display P3
  • EXIF Integration: The previously extension-defined eXIf chunk is now part of the main specification
  • Backward Compatibility: Maintains full compatibility with older PNG decoders which will display the static image in animated PNGs

Animation Comes to PNG… Officially

While APNG (Animated PNG) has been widely implemented in browsers and image viewing applications for years, it has never been part of the official PNG specification until now. PNG 3.0 formally adopts the APNG format by incorporating three specific chunks:

  • acTL (Animation Control): Defines overall animation parameters including frame count and loop count
  • fcTL (Frame Control): Specifies timing, position, and rendering information for each frame
  • fdAT (Frame Data): Contains the image data for frames after the first frame

This standardization legitimizes what has been a de facto browser standard for years, ensuring future consistency in implementations.

Bringing HDR to the Web

The addition of HDR support represents a major leap forward for PNG, enabling the format to properly represent high dynamic range imagery with wide color gamut. This is accomplished through several new chunks:

  • cICP: Contains color space metadata for video signal type identification, supporting formats like BT.2100 which is used for HDR content
  • mDCV (Mastering Display Color Volume): Describes the characteristics of the display used to master HDR content
  • cLLI (Content Light Level Information): Provides peak and average luminance information essential for proper HDR tone mapping

These additions allow PNG images to take advantage of modern HDR displays, supporting both PQ (Perceptual Quantizer) and HLG (Hybrid Log-Gamma) transfer functions.

Enhanced Metadata Support

The specification also formally incorporates the eXIf chunk, which was previously defined only in the PNG extensions document. This brings better support for Exchangeable Image File Format metadata directly into the main PNG standard.

Industry Impact

These changes bring PNG up to date with modern media needs while maintaining the format's core strengths: lossless compression, transparency support, and wide compatibility. The official standardization of animation support is particularly noteworthy as it validates a feature that has been implemented by browser vendors for years.

According to the W3C PNG Working Group, these updates reflect the organization's commitment to keeping the PNG standard relevant in an era of evolving display technologies and web capabilities.

The new PNG 3.0 specification is available at the W3C website.

For developers and graphic designers, the PNG 3.0 specification opens up new possibilities for creating more dynamic and visually rich content while maintaining the format's trademark lossless quality. The HDR support in particular positions PNG as a viable format for high-end photography and professional media production where accurate color reproduction is critical.

Web developers can expect major browsers to fully support these new features in the coming months, though most already support the APNG format that has now been officially standardized. The transition should be seamless for most users, as the specification maintains backward compatibility.

Written using GitHub Copilot Claude 3.7 Sonnet in agentic mode instructed to follow current codebase style and conventions for writing articles.

Source(s)

  • W3C PNG 3.0 Specification
  • Mozilla Developer Network - APNG
  • W3C PNG Working Group
  • TPU