JXL to DNG Converter

Encoding: the JXL uses lossy VarDCT or lossless modular coding; existing JPEGs can be repacked without loss; DNG uses lossless (or lossy) JPEG-compressed sensor data, plus optional JPEG previews, and the download is a Linear DNG: demosaiced 8-bit RGB with the colour matrices raw editors need.

Bit depth: 8 to 16 bits per channel, or floating point in the JXL; DNG allows 8 to 16 bits per channel, and the DNG written here has 8 bits per channel, linearised. High-bit-depth JPEG XL files are reduced to 8 bits per channel.

Colour: sRGB, Display P3, linear and other spaces described in the codestream in the JXL; DNG supports camera RGB plus the colour matrices that map it to XYZ (demosaiced linear RGB in a Linear DNG), written here as 8-bit sRGB.

Transparency: the JXL stores it as an extra channel in the codestream; the DNG has none, so transparent areas are filled with the colour you choose.

Animation: frames inside a single codestream; the DNG holds one image, so only the first frame is converted.

Metadata: the JXL can carry EXIF and XMP boxes in the container form, often stripped by encoders; DNG can carry EXIF, XMP and DNG tags for colour matrices, calibration and lens corrections, but nothing is copied across.

JPEG XL is a next-generation format designed to replace JPEG. It compresses better than JPEG and WebP, supports lossless, HDR and progressive decoding, and can losslessly repack existing JPEGs.

A JPEG XL file is either a bare codestream starting with FF 0A or an ISO base media container whose 'jxlc' box holds the codestream. A recompressed JPEG keeps a 'jbrd' box that lets the original JPEG bytes be rebuilt exactly.

JXL files usually come from image editors, archival pipelines and lossless JPEG recompression.

DNG is Adobe's openly documented raw format. Some cameras and phones record it directly, Adobe DNG Converter turns other brands' raw files into it, and a Linear DNG holds already-demosaiced RGB that raw editors treat like any other raw file.

DNG is built on TIFF/EP. The raw image sits in a sub-IFD marked as the main image, with tags for black and white levels, colour matrices and the colour filter pattern; a Linear DNG (PhotometricInterpretation 34892) stores demosaiced RGB instead of a mosaic. Previews are optional, and Adobe DNG Converter can write a medium (1024 px), full-size or no preview.

DNG is the better choice for raw editing and archiving raw files in an open format, while JXL suits archiving and future-proof high quality storage.

DNG strengths: Open specification read by every raw editor; Lossless compression and optional previews; Recorded directly by Leica, Pentax, DJI drones and phones. Drawbacks to weigh: Large files; No browser or ordinary photo viewer support on every platform.