Practice is never optimal. Customers send me CMYK Tiffs. I rather have RGB ones with assigned color spaces but practice ..... There may not be a better file available, it is often wiser to do a conversion yourself than the customer have a go at it and workflows through a RIP with whatever device link profiles or CMYK-device color management are not always the better road for several reasons. So I convert a CMYK Tiff directly to the printer/paper profile in Photoshop's CS 5.5 Profile to Profile and save the TIff with assigned paper profile. Intending to print that with Qimage and its CM off, printer driver CM off too. As CM conversion has been done already in the Photoshop phase, either with perceptual rendering or relative colormetric. Qimage will not accept the Tiff. I guess there still is some CMYK flag hanging in that file. When I convert the image right away to the highest quality JPEG this does not happen. There should not be a quality drop in the JPEG but I wonder what happens that Qimage refuses the converted Tiff.

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Met vriendelijke groet, Ernst

http://www.pigment-print.com/spectralplots/spectrumviz_1.htm
December 2012, 500+ inkjet media white spectral plots. 

Hello Mike,

Did you change something in the thumbs display between 115 and 119?  I have the same files converted to RGB+printerprofile and now they show in the thumbs section but also the CMYK Tiffs show without an error message. But one with a Fogra CMYK profile assigned that still gives the Image Read Error. That one will load into the editor and the image is displayed there. The only abnormality I can find now. None of the CMYK Tiffs (Fogra and Swop profiles assigned) will load in the print page which is correct. The Fogra one converted to RGB+printerprofile shows in the thumbs and can do everything a normal RGB TIff can.

With this outcome I can not complain though it would be better if all the CMYK Tiffs have the Image Read Error in the thumbs section and none can load to the editor or print page. OR... when this is a transfer stage in Qimage development if you intend to add CMYK as a supported file format one way or another. I doubt the last and can manage without that feature.

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Met vriendelijke groet, Ernst

http://www.pigment-print.com/spectralplots/spectrumviz_1.htm
December 2012, 500+ inkjet media white spectral plots.