2002.07.11 04:52 "Re: YCCK photometric?", by Chris Cox
The recently published Adobe Photoshop TIFF Technote indicates that the photometric must matched the jpeg compressed data so YCCK can't be used.
That is correct - YCCK is not valid in TIFF.
And the technote for JPEG in TIFF that covers that restriction is quite old.
I had hoped that the next TIFF spec revision would add a PhotometricInterpretation value for YCCK, thus allowing the requested behavior in a clean fashion. I take it that the above-quoted technote doesn't do that?
I haven't seen a request for that color model to be added to TIFF..... I'll have to check with Scott Foshee and see if he's received any such requests.
No, the technote says what Dwight paraphrased: the JPEG color model must match the TIFF color model.
Most of us have been trying to steer print professionals away from using CMYK in JPEG -- because they always expect perfect percentages without understanding that JPEG is lossy.