RAW to JXL Converter

Encoding: the RAW uses uncompressed, lossless JPEG or vendor-specific coding of the sensor data, depending on the maker; JXL uses lossy VarDCT or lossless modular coding; existing JPEGs can be repacked without loss, and the download is a JPEG XL encoded with libjxl compiled to WebAssembly, lossy at the quality you choose or lossless.

Bit depth: 12 to 16 bits per channel in the RAW; JXL allows 8 to 16 bits per channel, or floating point, and the JXL written here has 8 bits per channel. The sensor's 12 to 16 bits are not used: the camera's 8-bit preview is converted.

Colour: camera-native RGB from a colour filter mosaic in the RAW; JXL supports sRGB, Display P3, linear and other spaces described in the codestream, written here as 8-bit sRGB.

Metadata: the RAW can carry EXIF and vendor maker notes, almost always with an embedded JPEG preview; JXL can carry EXIF and XMP boxes in the container form, often stripped by encoders, but nothing is copied across.

Camera RAW files (CR2, CR3, NEF, ARW, DNG, ORF, RW2, RAF and others) hold the unprocessed sensor data from a camera along with an embedded full-size JPEG preview rendered by the camera.

.RAW is an extension rather than one format. Panasonic and Leica compacts wrote TIFF-like .RAW files before Panasonic moved to RW2, and scanners and scientific cameras use .raw for headerless dumps with no width, height or layout recorded, which nothing can read without being told those values.

RAW files usually come from older Panasonic and Leica compacts that saved .RAW, and scanners or scientific cameras that use the extension for pixel dumps.

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 is the better choice for archiving and future-proof high quality storage, while RAW suits editing in Lightroom, Capture One or darktable.

JXL strengths: Excellent lossy and lossless compression; Progressive decoding and HDR; Huge image sizes. Drawbacks to weigh: Browser support is limited (Safari only by default); Few apps can open it yet.