Expert: Amy - 7/31/2007

Question
I work in a pre-press department of a print shop and we are always receiving files that are built in the rgb color mode. When we convert these to cmyk we get the 4c black conversion, My question is : Is there a way I can set it up so that when we convert the file, the black doesn't go to 4c black? I would appreciate any info you might have on this issue.

Thank you,
Jim Cheney
ABS Graphics
Addison Ill

Answer
Hi Jim,

You could turn your black generation to maximum in Edit > Color Settings > Working Spaces CMYK > Custom CMYK > Black Generation. Then convert your doc to CMYK.

I think that will affect the other dark colors, though. Science tells me it will. The conversion engine can't tell what mixes of RGB are black and which aren't, you know?

So I copied this tidbit from another guy on the Adobe Forum.  I bet this is what you already do to fix the rich black.

-Amy Pace

Copied from Adobe.com forums:
Depends on the nature of the image. If there is nothing but white behind the black, I use this technique:

Select the black areas, hit copy.
Switch to black channel, hit paste.
Adjust CMY curves from 100% to 0%, adjust K curve ~75% to 100%.

This copies the full range of image information into the black channel and then "bumps up" the black channel so that the K is 100% and not 87% or what have you.

If we're talking a photograph (in which case I can't see why you'd want the blacks 100% K), use Select Color Range to select the blacks, adjust your selection edges via feathering or expand/contract, select similar, etc. and apply the curves as above. Be warned the blacks will look washed out compared to the other colors and are likely to have a "halo" effect of CMY black if you under-select or the surrounding color is likely to darken if you over-select.

End of copied information.