Nikon Electronic Format

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Also known as

• NEF
• Nikon Image Format
• Nikon Digital SLR Camera Raw Image File

File extension(s)

• .nef

Format registry information

• PRONOM

Preservation issues

• NEF is a proprietary format with an unpublished specification.
• NEF files can be very large - 70 MB or more.
• Xena incorrectly guesses the file type as TIFF and normalizes as it would a TIFF, with the result that a very large file (e.g. 70 MB) is normalized to a very small one (eg. 250 KB) with considerable loss of data. Changes to the raw file (ie: alterations done in image editing software) are stored in a separate XMP file, which Xena also does not recognize, and does not normalize together. This means that any edits added by the creator are removed.
• Possible preservation plan is normalization to Adobe Digital Negative (DNG) format
  • Library of Congress states that Adobe Digital Negative (DNG), Version 1.1 may be emerging as a standard preservation format for raw camera images.
    • Adobe provides a free (but not open-source) Adobe DNG Converter designed for downloading to Windows or Mac computers.
    • An open-source option for converting RAW image files to DNG is DigiKam.
• Another preservation option is conversion to JPEG2000 using ImageMagick

Conversion test results

• NEF conversion tests

More information

• NEF is a raw (i.e. pre-processed) image format produced by Nikon cameras.
• Information on NEF files is available at Library of Congress Sustainability of Digital Formats: Camera Raw Formats.
• For more information on JPEG2000 see Universal Photographic Digital Imaging Guidelines: Archiving and Technology Watch Support:JPEG 2000 - a Practical Digital Preservation Standard? Digital Preservation Coalition 2008.