PDF Association Plans to Make JPEG XL the Preferred Image Format for PDFs

The PDF Association has announced its intention to incorporate JPEG XL as the preferred image format within the official PDF specification. This move is expected to provide renewed momentum for JPEG XL, a modern image format that had previously faced setbacks in industry adoption.

JPEG XL is recognized for its advanced technical capabilities, including support for high dynamic range (HDR) imaging, extended color spaces, ultra-high-resolution images with more than a billion pixels, and the ability to handle up to 4099 channels with 32 bits per channel. These features make it particularly appealing for professional environments that require exceptional image quality and precise color fidelity.

Originally designed as the successor to the longstanding JPEG format, JPEG XL leverages technology from both the Free Lossless Image Format (FLIF) and Google's PIK project. The first version of JPEG XL was released at the end of 2020, and its standardization was completed in October 2021 under ISO/IEC 18181, with an updated second edition following in 2024.

Despite early enthusiasm, JPEG XL encountered significant challenges when Google decided to remove its experimental implementation from Chrome and Chromium browsers at the end of 2022. The company cited insufficient interest across the broader ecosystem as the reason for discontinuing support. This decision was met with considerable criticism from developers and industry professionals, as documented by the high number of responses and upvotes in related Chromium bug reports.

The landscape for JPEG XL support remains fragmented across browsers and operating systems. Apple has added basic compatibility to iOS and macOS, though its Preview app only allows users to open, not save, images in the JXL format. Safari does not support progressive rendering or animated images in JPEG XL. Microsoft has introduced a Windows 11 extension that enables support for the format, but its Edge browser, which relies on Chromium, does not natively support JPEG XL.

Mozilla initially mirrored Google's stance but later introduced experimental JPEG XL support in Firefox Nightly. As of September 2024, Mozilla indicated that full integration would be considered upon the availability of a decoder written in Rust, citing security concerns with the existing C++ reference implementation due to its size and complexity.

The potential adoption of JPEG XL as a core standard for images in PDF documents could influence its relevance and adoption rate, especially given that widely used PDF viewers, including those integrated into Chrome, would benefit from supporting the format. However, widespread use of JPEG XL for web images and other digital content remains dependent on broader browser compatibility, which has not yet been achieved three years after Google's withdrawal of support.

Industry observers will be watching closely to see if the upcoming changes to the PDF specification prompt a reassessment of JPEG XL's status among major browser vendors. While the inclusion in the PDF standard may increase its utility for professional and enterprise use cases, mainstream adoption will likely depend on coordinated support across platforms and browsers.