2003.01.27 19:48 "RE: Are there de facto defaults for resolution (TIFF 6 file) ??", by James Belshan
unfortunately some very odd folks put the resolution into a exif block in a tiff and not in the main tag table for a page. sucks, but in such circumstances you can only get the right into if you parse exif blocks too.
That's certainly true for JPEG, but the EXIF data is encoded as TIFF tags anyway - there *is* no EXIF block for TIFF...
Thanks for your help, guys. I've now researched the EXIF format a little, and can't find it within my TIF file. The files contain exposure information, though, which to me implies EXIF info.
My picture is CCITT bilevel, not JPEG. So my initial thought that EXIF info would be in JPEG-encoded image data within the image data can't be correct. I don't see the EXIF tag (#34665) in IFD 0, and there is no IFD 1.
In a nutshell... I'm still lost trying to find this (apparently EXIF) resolution information. But hey, on the bright side, I'm learning how to program image processing programs.
P.S. Here's all the TIF tags for IFD 0, in case you want to see them.
Tag #, Tag Name, ValueOffset
256, ImageWidth, 4600
257, ImageLength, 7000
258, BitsPerSample, 1
259, Compression, 4
262, PhotometricInterpretation, 0
273, StripOffsets, 228730
277, SamplesPerPixel, 1
278, RowsPerStrip, 28
279, StripByteCounts, 229730
284, PlanarConfiguration, 1