Bringing the K from grayscale to CMYK

700 views5 repliesLast post: 1/27/2004
I scanned a pen and ink image into grayscale mode. After converting to CMYK, using the eye dropper, I found out that there are CMY values together with K value.

Is it possible to convert a grayscale image to CMYK, removing the 3 colours, leaving only K??
#1
What are you trying to accomplish? If you're printing only grayscale, why did you convert to CMYK in the first place?

Bob
#2
Parka,

Create a custom CMYK profile in your Color Settings dialog and set black generation to Maximum. When you go to convert your grayscale image to CMYK, the CMY channels will be empty, the black will be the only channel to contain any information.

You can also do this by copying your grayscale image to the clipboard, create a new document (size should automatically be that of the clipboard contents) in CMYK color (make sure that you have a white background layer, not a transparent layer). All four channels should be empty. Select the black channel and paste the clipboard contents into that channel.
#3
wrote:
I scanned a pen and ink image into grayscale mode. After converting to CMYK, using the eye dropper, I found out that there are CMY values together with K value.

Is it possible to convert a grayscale image to CMYK, removing the 3 colours, leaving only K??

Certainly - just dop your conversion, then copy and paste the K channel to a new image.

This is often used as a way to get a variable density black channel, since you can vary the GCR setting to determine how heavy the K channel will be.

The curvemeister plugin will do this for you, allowing you to see the K channel in a variety of GCR settings before you copy it to the clipboard. --

Mike Russell
www.curvemeister.com
www.geigy.2y.net
#4
Parka,

I'll echo Bob's question....

If you just need a K channel, then just stick with greyscale.
#5
Is it possible to convert a grayscale image to CMYK, removing the 3 colours, leaving only K??

Image > Mode > Convert to Profile. Choose Custom CMYK, and set the black generation to Maximum (no UCA).
#6