DNG to PNG Converter

Encoding: the DNG uses lossless (or lossy) JPEG-compressed sensor data, plus optional JPEG previews; PNG uses lossless DEFLATE with a prediction filter chosen per row, and the download is a lossless 8-bit PNG with full alpha.

Bit depth: 8 to 16 bits per channel in the DNG; PNG allows 1, 2, 4, 8 or 16 bits per channel, and the PNG written here has 8 bits per channel. The raw data's 12 to 16 bits are not used: the embedded 8-bit preview is converted.

Colour: camera RGB plus the colour matrices that map it to XYZ (demosaiced linear RGB in a Linear DNG) in the DNG; PNG supports RGB, greyscale, or an indexed palette of up to 256 colours, written here as 8-bit sRGB.

Metadata: the DNG can carry EXIF, XMP and DNG tags for colour matrices, calibration and lens corrections; PNG can carry text chunks, an ICC profile, physical resolution and EXIF in an eXIf chunk, but nothing is copied across.

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 files usually come from Leica, Pentax and Ricoh cameras, DJI drones, Google Pixel and iPhone ProRAW, and Adobe DNG Converter.

PNG stores pixels losslessly with full alpha transparency. It is ideal for screenshots, logos, UI and anything with sharp edges, but photos saved as PNG are several times larger than JPEG.

A PNG opens with an 8-byte signature and is a chain of chunks, each with its own CRC: IHDR (size, depth, colour type), optional PLTE and tRNS for palettes, one or more IDAT chunks with the compressed rows, and IEND.

PNG is the better choice for screenshots, logos, graphics and anything that needs transparency, while DNG suits raw editing and archiving raw files in an open format.

PNG strengths: Lossless: no quality loss, ever; Full transparency with smooth edges; Perfect for text, screenshots and graphics. Drawbacks to weigh: Large files for photographs; No standard animation (that is APNG).