Re: how to compare inksets & gamuts
Re: how to compare inksets & gamuts
- Subject: Re: how to compare inksets & gamuts
- From: Steve Upton <email@hidden>
- Date: Mon, 30 Oct 2000 11:35:14 -0800
At 4:53 PM -0500 10/29/00, Richard N. Moyer wrote:
Maybe its useful (see below), if you know what you are doing. For
example, suppose you have a presumed wide gamut recording media,
such as an Ektaflex slide. You wish to print the image on that
slide. (instead of view it on a slide projector, or even scan it and
view it on your monitor). Now you have Chromix ColorThink, and you
are able to develop 3D gamut shapes of a multitude of profiles, some
of your scanner, some of your monitor, some of your working spaces,
and some of your various assorted papers, which have profiles.
Ideally what you would like to do (or at least I would like to do)
is to determine how much of the image on that slide can slip through
all the hoops of the various processes I am going to use, and come
out the other end (of the device/workflow tunnel) on paper. As a
starting imponderable, I don't know the gamut latitude of my image.
! (yes I have IT8 targets of Ektaflex, but I know nothing really
about my slide)
Although I really don't have Steve's ColorThink (yet), I have yet to
understand how this is going to tell me (exactly) where the pinch
points are in my workflow, or even give me specific directions as to
how to tweak devices, workspaces - to ream out everything so that
Ektaflex's "Gamut Potential" becomes realized - - on paper.
At this time ColorThink will not directly tell you how to do these
things. As an analysis tool it will allow you to view and contrast
the different profiles with each other to determine which ones have
colors outside the gamut of the others.
In the 3D gamut viewer you have the ability to turn one of the
wireframe gamut volumes white or some other color. This, along with
the ability to grab and rotate the two gamut shapes does allow you to
see the difference between two gamuts with a fair degree of detail.
You can, for instance, see how the RGB drivers for the Stylus 740
produce such poor shadow detail that many of the shadow colors
available in a DuPont Waterproof are not available on the 740 - and
as such the 740 is a bad proofer for the job unless a RIP is used to
recover this shadow detail.
Follow the link below to see an animate GIF of this comparison. The
animated GIF does not really do the graphing justice as you can open
the graph window to fill your entire screen and the detail and
clarity is much better.
<
http://www.chromix.com/images/cm/cct/3DGraph-gamutcomp.gif>
see this link for more info overall and other screen shots
<
http://www.chromix.com/pages/cm/cctoverview.html>
If Steve's software could "contrast and compare" multiple gamut
spaces in such a way that "voids", "gaps", "gamut omissions", or
"dropped data" are depicted, either graphically or with nice
diagnostics, actions might be taken by the user to "change the
entire system", from slide to paper. Now that might be progress.
These features have been requested and are in the works for future
versions. Numeric and "English" feed back is a very complicated thing
(to make simple and meaningful). In many ways, the (3D) picture is
worth a thousand words.
I should mention that you can take an RGB image, open it in
ColorThink and drag it onto the 3D grapher. The pixels are converted
to Lab and then graphed in 3D. Using this feature, and the 3D vector
compare function, you can compare two different images in 3D with
vectors (a line for each color depicting amount of color shift and
direction). If you have two different images - a source in your
working space and a "destination" in the printer's space - you can
graph the color shift that occurred when the image was transformed.
This will show how the colors in your image are remapped as they are
moved into the smaller(or different) gamut of the printer. This is
understandably a more advanced use of the tool but is available for
people interested in this level of analysis.
Working with 3D globs is difficult visually.
At first it can be a little confusing but I have many customers who
adjust to it fairly quickly and then wonder how they ever got along
comparing gamuts in 2D.
If you juxtaposition multiple globs onto a single "L" axis you have
"gibberish".
I respectfully disagree. Perhaps you have not had the chance to do so
using ColorThink. 3D juxtapositioning (love that word) of gamuts is
the most useful form of 3D graphing (next to 3D vector color shift
graphs) IMHO and presents a clear navigable diagram that allows
zooming and rotating to inspect white points, black points, gamut
boundaries and other points of interest on gamuts.
"Flying around" a single glob makes for nice sightseeing, but comes
up short on answers.
True, that's why 2 or more gamuts is very useful. Just drag another
profile onto the grapher and you're off.
Easier with multiple 2D slices, at various L values.
Easier yes but still less informative in my opinion. I don't really
think the 3D aspect is difficult and I have not had any complaints
yet.
But at the end of even this you really have not much more than
fatigue - - unless there was a structured analysis of your
system/intentions and implications.
This is a VERY valid point. Structural analysis is something that
needs work.....
Correct me if I am wrong. But I don't think we are there yet with
either our thinking (about this issue) or software.
I agree.
And, maybe we don't ever have to get that sophisticated until
someone invents both ink and paper that can theoretically hold the
"gamut potential" of the best recording media. We have a brilliant,
saturated "color basket" in the slide, and are attempting to place
it on (relatively speaking) a blotter paper. Perhaps 60 percent of
the "gamut potential" of the slide is lost.
This is true. I think it changes with practically every new ink jet
released (except for archival unfortunately, they continually play
catchup on the gamut size feature) but we have a ways to go before we
can print film gamut. It is also not possible to print film gamut in
some areas as the dynamic range of paper just doesn't correspond to
that of film.
At 1:37 PM -0400 10/28/00, Dan Culbertson wrote:
Also there is a nice commericial package called Chromix ColorThink from
Steve Upton at http://www.chromix.com which has a very nice gamut viewer
(among many other profile tools). Mac only so far though Steve is
entertaining the idea of a Windows version. Email him if you would buy a
Windows version since he needs to know if it is something worth doing.
Judging gamuts from 2D plots can be quite misleading. Gamuts are
really quite complex 3D shapes: 2D plots are useful as
visualization aids, but they're limited to a single luminance
level. You can produce many equally valid 2D plots that will give
you different answers.
Steve's tool lets you compare 3D gamuts in 3D, which is much more useful.
Thanks Bruce & Dan
Regards,
Steve Upton
+--------------------------------------------------+
Steve Upton
email@hidden
CHROMiX / Profile Central
www.chromix.com www.profilecentral.com
p:206-985-6837 f:206.526.8278
9594 1st Ave NE #390 Seattle, WA 98115
Color Store...Remote Profiling...Media Management
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