2002.08.15 16:34 "Re: Orientation field", by Daniel McCoy
I wish Adobe had never put that "optional" disclaimer in the TIFF 6.0 spec. This is a roadblock for TIFF usage. The exact same thing works well for PDF because there is no option to not implement it and still be compliant with the PDF spec.
Lets keep a little perspective here...
Adobe did not originally publish the TIFF 6.0 spec.
Adobe inherited TIFF when they bought Aldus.
The TIFF advisory committee that produced the 6.0 spec included people from a number of companies, so blaming Adobe for this is a bit unfair.
There are a few tags that probably should not have been optional, but ten years ago (the TIFF 6.0 spec is dated 1992) processor power and memory were a lot harder to come by than they are these days, so the extra burden of flipping images up-down, left-right was left as optional. Alternate solutions, such as tilting the head by 90 degrees, or using a mirror, were often considered to be more cost-effection solutions.
If the spec were written in these more enlightened times, I doubt anyone would argue for making implementation of the orientation tag optional.