CMYK Variation Software

[kaiserwilhelm]

We are having issues with gray balance on CMYK photos on our digital press.
The question arises - is there a software that will take Photo A and give me 50 different changes to it? IE, drop my CMY by 1 percent each. Increase by 2 percent, etc, etc?
Then, print out a variations page?

 

[Lukas Engqvist]

If you have grey variations try using heavier GCR to make the variation less noticable.

Don't know of any automatic way to do it, I guess it would be scriptable to duplicate the layer in Photoshop and then run a Channel Mixer on each copy. The question is your digital press stable over time? Many presses will vary with temperature and humidity, which again is an argument for stronger GCR in your images.

 

[Stephen Marsh]

A digital machine that I used to use had the following pros/cons:

* CMYK images with "regular" amounts of GCR designed for press use did not deliver balanced CMY neutrals due to the constant shift of the machine between calibrations. Sometimes, sending an RGB image was better as the in-RIP separation provided more neutral results.

* As Lukas correctly notes, for many digital machines, a very high/strong UCR or GCR separation is more stable and provides better gray balance.

Yes, one could write and action in Photoshop and use Bridge contact sheets or use a scripting language to do what you are asking. However, I think it would be better to look at your device ICC profile and see what a version with high UCR or GCR would do for your prints.


Stephen Marsh

 

[kaiserwilhelm]

Dear lord, I haven't worried about GCR or UCR since about 1992 when I was on a Crossfield scanner!!
This is a brand new digital web press. So far, color stability from hour to hour to month to month is QUITE good.
Just trying to create CMYK grayscales to give us a better looking pic. As you know, that makes the amount of CMY rather important. Two percent too much cyan and you are hosed.

 

[Lukas Engqvist]

What I have used is place greyscale tifs in InDesign. There they can be coloured with a swatch which i call rich grey. I give the swatch 20C 15M 15Y 100K. It's simple to adjust the tone in the images, just edit the one swatch to give cooler or warmer images.

 

[Emtri]

depending on what type of machine you run there are sometimes things you can do on the machine.
Ex: with konicas and the Fiery controller, you can globally adjust your lightness/brightness. It doesnt always work but it helps sometimes.

 

[Stephen Marsh]

If the primary concern of the final image appearance is neutral grayscale only with no colour, then it can often behoove one to:

a) Input the image as single channel grayscale data only, or
b) Input the image as empty CMY and K channel CMYK data only, or
c) Select RIP settings that treat single channel or neutral RGB input as K only, or
d) Separate the input image with a strong UCR or GCR K component, or
e) Use a device ICC profile that uses a strong UCR or GCR K component

As digital output device gray balance is non-linear and often far from press gray balance, it can be tough to have neutral appearance throughout the tone scale if one favours CMY over K.


Sincerely,

Stephen Marsh

 

[rich apollo]

Dude! You're creating your own nightmare, BUT try this action I built for a photographer. You should have better luck by keeping the CMY out of the quarter-tones. The shadow-end can withstand more variance without a visibly noticeable difference.