PerlMagick is an object-oriented Perl interface to ImageMagick. Use this forum to discuss, make suggestions about, or report bugs concerning PerlMagick.
Photoshop ignores the normal TIFF format density setting, but reads its own special profile image meta-data if present.
You will need to remove or modify that profile if you want photoshop to see the right density
NOTE I am not a Photoshop user, or even a PC user, so I only have the raw notes shown in the link above.
I would gladly accespt a HTML re-write of the above section by someone with more knowledge.