2008.10.01 16:02 "Re: [Tiff] Image Orientation tag and rotating images", by Edward Lam
It seems like hardly any software supports the orientation tag correctly. It seems that perhaps Photoshop does things correctly.
This is very true. On the other hand, the TIFF6 spec states that only the default value, 1 (ie. top-left), is required for baseline tiff readers. Over here, we've completely given up on trying to output .tiff files with non-default orientation values because of problems encountered by our users when using them with other packages.
Ultimately, there should be at least two output choices: one for baseline tiff files, and another for users who have tools that support the non-baseline values of the orientation tag.