11:37 p.m.
On Dec 10, 2003, at 7:13 AM, Marttila Jouni wrote:
Hello!
Here is an example connected to this discussion. I have compared
ECI-RGB and
Adobe RGB with CMYK output profile (this has been made on sheet-fed
press
using quite high print densities to get wide gamut).
I have taken out two examples on different L-levels. On L 43 CMYK
profile
exceeds clearly Adobe RGB on magenta shades (almost ECI also) and
especially
on higher L-level CMYK exceeds Adobe RGB on yellow areas but is still
inside
Eci-RGB.
I don't know if this is correct way of looking - please correct me if
I am
wrong. However it looks like when using special printing condition
meaning
high print densities ECI-RGB seems to be better choice than Adobe.
Well yes if you're going to print just a bunch of solid patches which
were originally RGB, I have no doubt at all that you'll get better
results using ECI-RGB. But how many people are printing millions of
impressions of calibration/profile targets and getting paid for it? No
one. A far more practical test involves taking a series of digital
captures (originals) and converting each to ECI-RGB and then go back to
the originals and convert them to Adobe RGB. Take each set (Adobe RGB
and ECI RGB) and convert to CMYK. Now print them out and see what you
get.
If you're going to take a given set of RGB numbers and merely assign
ECI-RGB, then convert to CMYK; go back to the same set of RGB number
and assign Adobe RGB and convert to CMYK, then sure the ECI-RGB will
invariably look better (in terms of saturation). But those colors that
exist in ECI-RGB but not in Adobe RGB but could be printed (especially
to a press) are not very common.
And for image editing, it's like looking through a tunnel because
there's a considerable amount of color that exists in ECI RGB that
cannot be displayed on a CRT or LCD.
Chris Murphy
Color Remedies (TM)
www.colorremedies.com/realworldcolor
---------------------------------------------------------
Co-author "Real World Color Management"
Published by PeachPit Press (ISBN 0-201-77340-6)
12:33 a.m.
New subject: Re(4): Re: ECI-RGB / Any advantages?
Hi Chris,
lists(a)colorremedies.com wrote Fri, 12 Dec 2003 15:37:42 -0700
[...]
If you're going to take a given set of RGB numbers
and merely assign
ECI-RGB, then convert to CMYK; go back to the same set of RGB number
and assign Adobe RGB and convert to CMYK, then sure the ECI-RGB will
invariably look better (in terms of saturation). But those colors that
exist in ECI-RGB but not in Adobe RGB but could be printed (especially
to a press) are not very common.
if I try to take your reasoning one step further, in lieu of better (and
readily available) gamut mapping paradigms, it may be useful to have
let's say a set of RGB editing color space/profiles, each of which is
targeted at a certain class of output devices, e.g. one for newsprint,
one for web offset, one for commercial printing and one for high quality/
large gamut ink jet devices (list definitely neither exhaustive nor
necessarily representative...).
If I knew I am only going to do newsprint and web offset for a given
image, I'd maybe use the web offset oriented flavor of that RGB editing
color space/ICC profile, and would increase the probability that what I
see on my screen (colors, detail, etc.) can be output at least more
predictably, than if I used an RGB editing color space/profile instead
that comprises all the colors for commercial offset printing on glossy paper.
A question that comes to my mind: let's assume I have a digital camera
shot covering quite some gamut, and I also have some way to get the image
data out of the camera without spoiling it by some early/inadequate
conversion into some questionable color space/ICC profile. If I convert
such data to a 'smaller gamut' RGB editing color space - how do I control
the gamut mapping strategy (only printer profiles really support
rendering intents)? If all goes bad, I have already "lost everything"
when I reach my process specific editing color space.
Olaf Druemmer
5:08 p.m.
New subject: Re(4): Re: ECI-RGB / Any advantages?
On lørdag, dec 13, 2003, at 00:33 Europe/Copenhagen, Olaf Drümmer wrote:
it may be useful to have
let's say a set of RGB editing color space/profiles, each of which is
targeted at a certain class of output devices, e.g. one for newsprint,
one for web offset, one for commercial printing and one for high
quality/
large gamut ink jet devices (list definitely neither exhaustive nor
necessarily representative...).
The idea of an image archive is to preserve capture colors in the
source space which may be exploited in destination spaces the size and
shape of which cannot be foreseen at creation time.
IFRA used to advocate ColorMatch RGB for newsprint. This one can do for
dedicated processing, but how many people create content only for one
printing condition?
Color is already far too complicated, unfortunately.
Thanks,
Henrik
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2 comments
3 participants
participants (3)
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Chris Murphy -
Henrik Holmegaard -
Olaf Drümmer