CMYK separations

[Niels Rasmussen]

Simple question - can I save and use the individual channels generated by CM in WgCMYK mode to create separations for gum printing?

[-default]

It's possible, and might be interesting to experiment with, but it's probably more trouble than it's worth, and the blues would be too weak. 

If you are using Elements, though, this would provide you with access to generating CMYK channels.  As it turns out, I'm doing a release with more control over the GCR value, that might be interesting.

If you have full Photoshop, I recommend that you experiment with custom CMYK profiles in Photoshop, where you have individual control over the various color curves in the profile.  Once you have a profile you like, you can re-use it easily in Photoshop.

Your process is similar to dye transfer, and a lot of work has been done using Photoshop to generate the matrices for this process: http://www.dpug.org/forums/f9/dye-transfer-process-done-digitally-298/ .  My dear friend Ctein is a good reference for digital dye transfers: http://ctein.com/dyetrans.htm

You can approximate Curvemeister's separations in Photoshop by creating a custom CMYK profile in Photoshop whose primaries approximate those in Adobe RGB, specifying zero dot gain.  Before Curvemeister existed, I made a profile that did this: http://curvemeister.com/tutorials/widegamutcmyk/index.htm

Mike

[pictus]

Take a look http://sean-blog.twicebakedphoto.com/2010/10/cmyk-in-rgb-explained.html

[-default]

Pictus,  very interesting.  This is exactly what Curvemeister does internally.