It sounds like the initial jpeg was of very high quality. Images vary, although I'm still somewhat surprised.
The guy at the copy shop could have used a PS plug-in like OnOne's Perfect Resize (Genuine Fractals). Still, i hear you - there's only so much that can be done, unless the guy used it to up-sample and then up-sample again...?
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I just realized that Preview has a "resize image" feature as well.
Does anybody know if there's anything inferior about Preview's resize image features vs. Photoshop's?
When I resized it to 7200x8866 in Preview, the result was a 3.6MB Jpeg which to my eyes looks no different than the 191MB TIFF that the guy created for me, or the 11MB Jpeg that he created for me.
Am I right in assuming that there actually might not be any difference at all between those three files, since the source file was a 133KB file at 480x579? Am I not really going to be missing anything that could have been there if I use the 3.6MB 7200x8866 Jpeg? They really look the same to me.
FWIW, I personally would trust Photoshop over Preview with something like this any day of the week. Adobe's been making Photoshop for many years, and it's industry-standard software. Preview... not so much.