Re: Offset printing
Re: Offset printing
- Subject: Re: Offset printing
- From: Terry Wyse <email@hidden>
- Date: Sun, 02 Dec 2001 07:50:19 -0500
on 12/1/01 7:28 PM, Andy D'Angelo wrote:
>
> One of our recent brochures had an image on the cover which printed
>
> somewhat dark...client acceptable, but slightly dark. The printer
>
> suggested the seps looked "muddy" implying there was too muck black
>
> in the midtones. His suggestion was to take out black...but , he was
>
> vague about how to do this. This was a digital shot, converted to
>
> CMYK; SWOP, coated, 20%,GCR, Heavy, Gamma2.2. Dot Gain 20%. Any
>
> suggestions would be appreciated.
First off, sounds like you're mixing some terms from your RGB and Grayscale
working spaces into the description of your CMYK setup plus you didn't
mention what your TAC or total ink limit was set to. Nevertheless....
"Muddy" separations don't inherently imply there's anything wrong with the
black separation UNLESS they failed to control their black dot gain on
press. It could mean they have an OVERALL dot gain problem or you're not
giving them separations suited to their printing process. I would do these
three things:
* LOWER your total ink setting at least 20% from what it is now. As a rough
guide, you ought to be around 280-310% for a coated sheet on web and
300-340% for coated sheetfed, much less if it's an uncoated sheet.
* INCREASE your dot gain setting 3-5% to 23%-25%. This will cause it to
separate LIGHTER when converting from RGB to CMYK.
* Lastly, set your black generation to GCR Light or Medium instead of Heavy.
If they have any black dot gain issues, this should make your separations
less susceptible to this problem as it will remove black and replace it with
a corresponding amount of CMY.
Hope this helps..
Terry
_____________________________
Terence L. Wyse
Color Management Specialist
All Systems Integration, Inc.
http://www.allsystems.com
email@hidden
_____________________________