2001.01.12 21:48 "What is the proper number of bytes in a TIFF 6.0 "word"", by Dave Abercrombie

2001.01.12 22:21 "Re: What is the proper number of bytes in a TIFF 6.0 "word"", by Helge Blischke

The TIFF 6.0 spec uses the word "word" a little losely. In the description of an Image File Header, bytes 4-7 are an offset in bytes of the first IFD, and then goes on to say that the IFD "must begin on a word boundary". But there is no mention there of the size of a "word".

Shortly thereafter, in the description of an IFD, bytes 8-11 contain the Value Offset. "The Value is expected to begin on a word boundary; the corresponding Value Offset will thus be an even number." I suppose this answers the question, but if a "word" were four bytes long, it would still be even.

If I'm not mistaken, a "word" was a dominant term in the days of the 16-bit architecture; and C had to make the distinction between a "short" and a "long" (word). Since TIFF 6.0 was finalized in 1992, I suppose one could presume that words were predominantly two bytes at the time.

What is the consensus among the TIFF experts?

If you look at figure 1 (page 14 of the spec), I think it is clear that a "word" is meant to be a 2 byte quantity, though the spec doesn't define this term.