TIFF to DNG Converter

Encoding: the TIFF uses none, LZW, PackBits, Deflate or JPEG, chosen per file; 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: 1 to 16 bits per channel, or 32-bit floating point in the TIFF; DNG allows 8 to 16 bits per channel, and the DNG written here has 8 bits per channel, linearised. 16-bit and floating-point TIFFs are reduced to 8 bits per channel.

Colour: RGB, CMYK, Lab, greyscale or palette, often with an ICC profile in the TIFF; 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 TIFF stores it as an extra sample declared in the ExtraSamples tag; the DNG has none, so transparent areas are filled with the colour you choose.

Other images: the TIFF can hold several pages, each in its own image file directory; only the main image is converted.

Metadata: the TIFF can carry EXIF, XMP, IPTC and ICC, all stored as tags; DNG can carry EXIF, XMP and DNG tags for colour matrices, calibration and lens corrections, but nothing is copied across.

TIFF is the professional archive and print format. It can hold multiple pages, high bit depths and lossless data, and is common in scanning, publishing and GIS.

A TIFF begins with 'II' or 'MM' for the byte order and the number 42, then an offset to the first image file directory (IFD): a table of tags giving the size, compression, colour model and the location of the strips or tiles of pixels. Each further page is another IFD.

TIFF files usually come from scanners, print and publishing workflows, photo archives and tethered camera capture.

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 TIFF suits printing, scanning and archival masters.

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.