[argyllcms] Re: Accounting for dot gain in press simulation
- From: Craig Ringer <craig@xxxxxxxxxxxxxxxxxxxxx>
- To: argyllcms@xxxxxxxxxxxxx
- Date: Thu, 03 Mar 2011 10:52:39 +0800
On 02/03/11 20:10, Graeme Gill wrote:
> Alastair M. Robinson wrote:
>> By the way, a 60-70% tint of each colour in a band all the way across
>> the sheet (perpendicular to the sheet's direction of travel in the
>> press) is another useful trick - an uneven screen is another immediately
>> visible sign that duct settings were uneven. (I wouldn't be surprised if
>> a profiling chart "tracked" through a screen to some extent, though,
>> since the total ink coverage over the length of the sheet can change
>> abruptly from column to column.)
>
> Sounds like excellent advice. A CMY grey bar right across the page too
> (at the
> recommended percentage for grey for their press setup) is also probably
> a good thing.
Once again, thanks for the advice. I'll do just that.
I'm waiting to confirm the imposition of the pages with the printer so I
know whether I need to add my grey and tint bands across the long or
short edge of the paper. I'm assuming the long edge for now.
I have four 265x405mm pages to play with, each printed with a blank reverse.
I'm building my target with:
~/bin/targen -G -v 1 -d 4 -e 40 -g 50 -f 2800 -c ../News_Oct09.icc rural
I've used lots of extra white measurements because it's off-white
newsprint. The CMY grey steps are because - after my last profiling
attempt - I want to focus on a uniform grey curve and a good match
between pure-K and CMYK greys, which means more samples of the more
unpredictable CMYK greys.
I'm then producing EPS targets for the 265x405mm printable area with:
~/bin/printtarg -v -p 230x405 -i i1 -e -m 0 -P -L rural
I'm using only 230mm of width to allow room for 5mm bands of CMY(K) rich
grey, plus C, M and Y 60% tint strips all the way across each page, with
a bit of separation between each. Wide enough? I can sacrifice some
patches to make it wider if 5mm isn't likely to be wide enough to be useful.
The final page will be used for the standard standard PANPA (Pacific
Area Newspapers Association) test print page to give the press operators
something familiar to play with and compare to.
Sound sane?
--
Craig Ringer
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