BigTIFF Design

This design details a 64-bit (larger than 4GB) TIFF format specification. The design is based on a proposal by Steve Carlsen of Adobe, with input from various other parties.


  • Version = 43

  • 8-byte offset to first IFD

  • Value/Offset fields are 8 bytes

  • 8-byte offset to the next IFD

  • add TIFFType of LONG8, an 8 byte (unsigned) int

  • StripOffsets and TileOffsets and ByteCounts can be LONG8

More Detail

  • The Version ID, in header bytes 2-3, formerly decimal 42, now changes to 43

  • Header bytes 4-5 contain the decimal number 8.

    • If there is some other number here, a reader should give up.

    • This is to provide a nice way to move to 16-byte pointers some day.

  • Header bytes 6-7 are reserved and must be zero.

    • If they’re not, a reader should give up.

  • Header bytes 8-15 contain the 8-byte offset to the first IFD.

  • Value/Offset fields are 8 bytes long, and take up bytes 8-15 in an IFD entry.

    • If the value is ≤ 8 bytes, it must be stored in the field.

    • All values must begin at an 8-byte-aligned address.

  • 8-byte offset to the Next_IFD, at the end of an IFD.

  • To keep IFD entries 8-byte-aligned, we begin with an 8-byte (instead of 2-byte) count of the number of directory entries.

  • Add TIFFTypes of LONG8 (= 16), an 8 byte (unsigned) int, and SLONG8 (= 17).

  • Add TIFFType IFD8 (=18) an 8byte IFD offset.

  • StripOffsets and TileOffsets and ByteCounts may be LONG8 or the traditionally allowed LONG or SHORT.

  • The proposed extension is .tf8, and call it “8-Byte TIFF”.

    Otherwise, it’s just like “original TIFF.” (“TIFF Classic?”)

Open Issues

  • What to call the new format

    • ChrisCox – I don’t think end users will understand what “8-byte TIFF” means

    • AndreyKiselev - 23 Sep 2004 – What about TIFF64? “64” is a widely used buzzword and should be directly associated with the 64-bit offsets and 64-bit architectures.

  • What 3 character file extension to use (gotta be DOS compatible)

  • What 4 character file type to use (for Macintosh)

  • What MIME type to use


Example files from Joris Van Damme.


  • TIFFType 13 is ttIFD, 14 is assigned to ttUnicode, and 15 is assigned to ttComplex. So, I changed the types for ttLong8 and ttSLong8 to 16 and 17, respectively.

    • AndreyKiselev - 23 Sep 2004 – Where are these fields defined? Is there any new Technical Note or something? And what is encoding behind the word “Unicode”?

    • ChrisCox - 27 Sep 2004 – They are in the Adobe TIFF definitions. I am still working on releasing updated TIFF documentation.

  • Added list of open issues.

  • settle on version 43

  • cleanup

  • TIFFType 18 (8 byte IFD) added.

  • Clarified that fields which may be LONG8 can also be one of the old supported types.