1999.06.10 15:50 "Re: What kind of TIFF is this?", by Helge Blischke

I am working with some 3d software that allows the placement of textures onto surfaces. Unfortunately, the only textures that seem to work are the ones that came with the 3d software. Anything I produce fails.

I tried opening this TIFF (link below) in Adobe Photoshop (WinNT) v5.0, then saving under a different name (yes, I tried all 4 possible setting combinations). The newly saved file refuses to be accepted, even though I didn't make any changes. The original file works. A byte-to-byte comparison of the two files reveals that they are very different. It seems that Photoshop is changing stuff, which results in an invalid file format (as perceived by my 3d software).

How can I produce TIFF files in same format that this one is? Or at least identify what the specifics are? Any help would be greatly appreciated.

Here is a link to the example TIFF file: http://www.azwebnet.com/wad/bmarble.tif

I checked the sample image (bmarble.tif); it's a pretty normal one. Here is the information displayed by tiffinfo and tiffdump, respectively:

TIFF Directory at offset 0xc008
    Image Width: 128 Image Length: 128
    Bits/Sample: 8
    Compression Scheme: none
    Photometric Interpretation: RGB color
    Orientation: row 0 top, col 0 lhs
    Samples/Pixel: 3
    Rows/Strip: 21
    Planar Configuration: single image plane

Magic: 0x4d4d <big-endian> Version: 0x2a
Directory 0: offset 49160 (0xc008) next 0 (0)
ImageWidth (256) SHORT (3) 1<128>
ImageLength (257) SHORT (3) 1<128>
BitsPerSample (258) SHORT (3) 3<8 8 8>
Compression (259) SHORT (3) 1<1>
Photometric (262) SHORT (3) 1<2>
StripOffsets (273) LONG (4) 7<8 8072 16136 24200 32264 40328 48392>
Orientation (274) SHORT (3) 1<1>
SamplesPerPixel (277) SHORT (3) 1<3>
RowsPerStrip (278) LONG (4) 1<21>
StripByteCounts (279) LONG (4) 7<8064 8064 8064 8064 8064 8064 768>
PlanarConfig (284) SHORT (3) 1<1>

It displays fine as well. I suppose the TIFF interpreter your 3d software uses is broken -- either it insists in MM (Motorola/Mac) format as your sample, and Photoshop creates an II (Intel) format, or your software can't cope with the private tag(s) Photoshop inserts into the TIFF IFD. I'd suggest to hack a bastard of the tiffcp utility that in included in the libtiff distribution to constrain the IFD to exactly those tags as in the sample file.

Helge

--
H.Blischke@srz-berlin.de
H.Blischke@srz-berlin.com
H.Blischke@acm.org