TIFF and LibTiff Mail List Archive


2000.10.04 16:24 "PHOTOMETRIC_YCBCR", by Raj Kumar S.
2000.10.04 16:17 "Re: PHOTOMETRIC_YCBCR", by Martin Bailey
2000.10.04 20:58 "Re: PHOTOMETRIC_YCBCR", by Rex Jolliff
2000.10.05 00:20 "Old-style JPEG and HP 9100C Digital Sender", by Tim Bell
2000.10.05 03:39 "Re: Old-style JPEG and HP 9100C Digital Sender", by Niles Ritter

2000.10.05 00:20 "Old-style JPEG and HP 9100C Digital Sender", by Tim Bell


We've got an HP 9100C Digital Sender (network connected scanner) and it seems to be producing Old-style JPEG TIFFs, which libtiff says it can't read. (We're using Linux for this.) I thought I'd check here before I sent a detailed bug report to HP tech support.

Running tiffinfo on one of the files gives:

        qcf6.tif: Warning, unknown field with tag 512 (0x200) ignored.
        qcf6.tif: Warning, unknown field with tag 513 (0x201) ignored.
        qcf6.tif: Warning, unknown field with tag 514 (0x202) ignored.
        qcf6.tif: Warning, unknown field with tag 519 (0x207) ignored.
        qcf6.tif: Warning, unknown field with tag 520 (0x208) ignored.
        qcf6.tif: Warning, unknown field with tag 521 (0x209) ignored.
        TIFF Directory at offset 0x17898

     Subfile Type: (0 = 0x0)

          Image Width: 1654 Image Length: 2339
          Resolution: 200, 200 pixels/inch

     Bits/Sample: 8
    Compression Scheme: Old-style JPEG
    Photometric Interpretation: YCbCr
    FillOrder: msb-to-lsb

   Orientation: row 0 top, col 0 lhs
  Samples/Pixel: 3

          Rows/Strip: 2339

   Planar Configuration: single image plane

          Page Number: 0-0

(From looking at the file, I realised that stripping off the first 8 bytes would give a JPEG, and that resulting file seems fine.)

Now, the HP tech support assure us that the 9100C produces "Compliant TIFF6.0 files". As I understand it, this is strictly true, because the DRAFT TIFF Technical Note #2 which redefines JPEG handling under TIFF is not actually part of a TIFF standard yet. However, TN#2 does include this: "TIFF writers are strongly discouraged from using the 6.0 JPEG design", so we should be able to use this to tell HP that they've implemented the wrong JPEG spec for TIFF.

The HP tech support people want to recreate our problem. I'm going to point them in the direction of the libtiff web page and software. Are there pre-compiled Windows binaries available? I don't know whether they'd go to the trouble of compiling their own.

Am I on the right track with all this? I'd really like HP to fix their product to use the revised JPEG encoding, and I figure giving them as much accurate info as I can can only help.


Tim Bell - - System Administrator & Programmer
    Trinity College, Royal Parade, Parkville, Victoria, 3052, Australia