Convert Black Separation into CMY

[chevalier]

I've got a really crazy one here. I need to convert the black channel in a Photoshop image into a CMY build. I'm looking for suggestions from who attempted such a crazy feat.

Why? - See attached PDF
Carton is CMYK + 3 Spots + Varnish + Coating (Utilizes every press unit - so a second black is out of the question)
The spot colors are in a logo (a big national brand) and are not reproducible with CMYK.
Lots of white knockout text on the carton - building the flood black is out of the question.
A heavy opaque black is to be used so that the black is "true" black.

This leads me to taking most of the black out of the CMYK photograph in order to prevent the opaque black from destroying it. We are G7 GRACoL Gray Balanced so we should be able to hit at least a very dark gray then have a touch of black.

Thoughts? Suggestions?

[chevalier]

Safari doesn't seem to place nice with the attachment manager. The attached PDF is Adobe Illustrator CS5 editable.

[rich apollo]

Is the large black solid the issue? I would recommend a 4 color black in the black solid. Run a 30c, 20m, 20y, 100k (or something similar). As long as the black channel is 100% you can build a spreadback on all the white text to mask misregistration - an intelligent trapping system will do this for you. That's gonna' be MUCH easier than trying to run a photo with no black. Should give you a plenty dark black.

[meddington]

I've done CMY only separations before...can't remember why exactly, but it was certainly a compromise in visual quality. If you have ProfileMaker, its easy to do. Apollo's suggestion is probably your best bet.

[DCurry]

Agreed about the rich black, but if you really want to eliminate K from the image you don't need any special software other than Photoshop. You can simply re-separate the image with your Black Generation set to None in the Custom CMYK options (under Color Settings). If you just want most of the black out choose Light.

If you find that you do this often, you can save the setting as an ICC profile and next time, instead of messing with your color settings (and possibly foregetting to change them back!), you can Convert to Profile.