Luminous Landscape Forum

Raw & Post Processing, Printing => Digital Image Processing => Topic started by: JeanMichel on August 09, 2010, 01:51:45 pm

Title: Output sharpening for cmyk printing
Post by: JeanMichel on August 09, 2010, 01:51:45 pm

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

Title: Output sharpening for cmyk printing
Post by: digitaldog on August 09, 2010, 05:43:02 pm

Sharpen, then convert.

Title: Output sharpening for cmyk printing
Post by: Schewe on August 09, 2010, 06:12:45 pm

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.

Title: Output sharpening for cmyk printing
Post by: JeanMichel on August 09, 2010, 06:35:11 pm

Quote from: 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.

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