5 Replies Latest reply on Jan 3, 2013 7:57 AM by MarieMeyer

# Can offset presses actually do 1% increments of C or M or Y?

When trying to achieve very bright colors, with no black, is it valid to move the other components in 1% increments: for example, 100*5*1*0? Or is that expecting a level of precision that is more than the press can actually deliver.

Years ago I worked with a printer who advised always rounding each of the 4 components to the closest multiple of 5. Obviously, controls are much more sophisticated these days. And, obviously, we spec out colors with 1% increments quite frequently. But can a press, in this case, one using the GRACol2006 profile, actually deliver? them?

Please note I'm not asking if 100*5*1*0 would be visibly different from 100*5*0*0. What I want to know is if I ask for 1% in one of the CMY channels, am I actually going to get it?

• ###### 1. Re: Can offset presses actually do 1% increments of C or M or Y?

Hello Marie,

It is possible to get precision at least of 0.4% increment in RIP for plates. Calculation is simple: 256 possible shades (tints): 100/256 = 0.390625.

This is how a gradient can be done with halftone.

Using a multiple of 5% ??? how could they make a smooth gradient?

In résumé, you can make incement of 1% for sure!

Hope this help!

Couleur911.com

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• ###### 2. Re: Can offset presses actually do 1% increments of C or M or Y?

It will depend on the actual press and the type of paper used.  It is possible to generate 1% increments in today's direct-to-plate environments.  Sometimes it depends on what the press operator had for breakfast.  Keep in mind that water balance or lack thereof and the fact that ink is tranferred to a blanket then onto the media all have to do with whether a certtain percentage can be achieved.

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• ###### 3. Re: Can offset presses actually do 1% increments of C or M or Y?

I found an interesting doc by Heidelberg:

http://www.heidelberg.com/corp/www/binaries/bin/files/dotcom/en/prinect/prinect_standardiz ation.pdf

Page 21 shows some tolerances for standardized offset processes:

Dot Gain: +-3% at the ends, +-4% in the middle

Inks C,M,Y,K: CIELab dE +-5%, Density +-8%

This sheds some light on the achievable absolute accuracy of levels and colors.

Whether ink inkrements of 1% can be reproduced measurably (density) is a matter

of process noise and parameter drifting, as John says..

But in fact this was the last question:

What I want to know is if I ask for 1% in one of the CMY channels, am I actually going to get it?

In my opinion it's impossible to achieve a safe reproduction of 1% ink.

Best regards --Gernot Hoffmann

• ###### 4. Re: Can offset presses actually do 1% increments of C or M or Y?

Was the quastion was about the minimum % that can be used to mix a cmyk color?

I agree that asking for a 1% could be trivial.

When I aswered Marie’s question, I was refering to the minimal % that could make a difference in a CMYK color build.

Just think about gradient… they have to have a minimum % difference to create smooth transition from one color to the other in a blend.

Best Regards,

Louis

• ###### 5. Re: Can offset presses actually do 1% increments of C or M or Y?

Hello all,

Thanks for the input. I had a meeting with our chosen printer yesterday. They state they can exectute on 1% incrememtnal steps (i.e. C59 to C60) but don't think they can do 1% absolute values (C1).

Thank you all for your help. It was great homework for this meeting!