Re: The final result in print between Euroscale and SWOP
Re: The final result in print between Euroscale and SWOP
- Subject: Re: The final result in print between Euroscale and SWOP
- From: Roberto Michelena <email@hidden>
- Date: Mon, 28 May 2001 15:46:06 -0500
From what I know, the ink standards are not that different. And be aware
that SWOP and Euroscale do not mean true ink specs, but rather industry
average colors which I believe don't specify tolerances.
ISO 12647, on the other hand, does specify ink in Lab terms with it's
tolerance.
Supposedly, ISO 12647 ink specs have a tolerance that allows usual SWOP
and Euro inks to comply, I believe even japanese ink standards are within.
But within doesn't mean in the center. A Norwegian company whose name
escapes me now printed a "color book" (these swatch bibles) using ISO
12647, and they prided a lot on being in the center of the defined ink
color specs.
Where SWOP and Euroscale do differ a lot is in dot gain. That's not
because of paper differences or ink differences, that's because of the
film and plate making process.
In Europe it's usual to work with positive film and positive plates
(except for newspapers), while in the U.S. the trend is negative film and
plate.
The total dot gain of a printing process is a sum of different gains and
losses in each step of the process. file-to-film, film-to-plate,
plate-to-print (called mechanical dot gain), and optical gain that occurs
when viewing a printed piece.
Film-to-plate, when working with positive plates, is actually a loss of
usually 3% in the midtones.
When working with negative plates, it's a gain of about 2% in the
midtones.
Thus, there's a difference of about 5% ; SWOP (neg plates) is 5% higher
gain than Euro (pos plates).
This usually translates to a total dot gain of about 17% for Euro and 22%
for Swop, when printing on coated stock sheet-fed commercial work.
Now, the setups in Photoshop... 20% swop and 9% euro, and however you
don't see an 11% jump on screen when switching from one to the other, do
you? I've always thought something weird is going on inside.
-- Roberto Michelena
EOS S.A.
Lima, Peru