Output sharpening for cmyk printing

[JeanMichel]

Hi,

If it is not too bold to ask, perhaps Jeff Schewe may answer this question. On pages 274 and 275 of his book "Image Sharpening" there is a recommendation for the method for output sharpening for halftone printing. The screen shot shows that the image is still in RGB. Am I correct to assume that this output sharpening is applied to after changing the image into cmyk.

Thanks

Jean-Michel

[digitaldog]

Sharpen, then convert.

[Schewe]

What Andrew says...

You really don't want to do sharpening on a file that has already been separated into CMYK (if you can avoid it) because the black channel changes the behavior of the way layer blending will happen. On the other hand, there is a technique for sharpening only the K channel to bring up some black channel detail that can be useful-but that's an "effect" technique, not a normal output sharpening approach.

[JeanMichel]

What Andrew says...

You really don't want to do sharpening on a file that has already been separated into CMYK (if you can avoid it) because the black channel changes the behavior of the way layer blending will happen. On the other hand, there is a technique for sharpening only the K channel to bring up some black channel detail that can be useful-but that's an "effect" technique, not a normal output sharpening approach.

Thank you both, that very much clarifies the reasons to do the final sharpening in RGB then convert.
Thanks again.
Jean-Michel