Re: U.S. Web Coated (SWOP)v2 vs. SWOP2006_Coated5v2
Re: U.S. Web Coated (SWOP)v2 vs. SWOP2006_Coated5v2
- Subject: Re: U.S. Web Coated (SWOP)v2 vs. SWOP2006_Coated5v2
- From: Roger Breton <email@hidden>
- Date: Fri, 04 Jan 2008 20:32:33 -0500
Todd
You raise a number of good questions.
First, the old SWOPv2 profile. It's been around for a while. It's made by
Adobe. It's distributed with the CS component applications. It's not bullet
proof but it's still a good performer.
Second, the 'new' SWOP2006_Cx profiles freely available. If you read the
disclaimer (did they removed them?), everyone who downloads and uses these
new profiles is on their own. Those new SWOP2006 profiles are not made by
Adobe but you may like what you see. I think they were made by Monaco
PROFILER with a light (heavier?) GCR. Similar to SWOPv2.
In own humble personal tests, I can't say it was love at first sight. Since
I have to tools to generate a SWOP2006 profile of my own, that's the route I
prefer to follow.
Eventually (when?), Adobe will come out with SWOP2006 profiles flavors of
their own. I'm not clear on what it is that is holding them (printing
politics?). But they will come out with their versions of SWOP2006 profiles
based on the SWOP2006 datasets.
The main differences in the two profiles, as far as I can tell, is their
respective gray balances aim points and the underlying press calibration
methods. SWOPv2 is based on TVI press calibration (20% dot gain, etc)
whereas SWOP2006 datasets are based on a proprietary press calibration
approach developped by Don Hutchison. With loads of post-processing
optimizations and data smoothing.
The origin of SWOPv2 is CGATS TR-001 1995 dataset. It's not freely available
but it's not very expensive. SWOPv2 can be used anywhere an ICC profile
conversion can be made (Mac, PC, Unix, etc.). The story of SWOPv2 is Thomas
Knoll. He used his own profiling software to create SWOPv2.
Don't be fooled by gamut size differences between SWOPv2 and SWOP2006_C5.
Insist on comparing the primaries and secondaries colorimetrically and
you'll be closer to the truth than any kind of gamut projection (you could
do Lch leaves but I wouldn't).
For now, I would not systematically assign SWOP2006_C5 to mystery meat CMYK
images because that wouldn't not be a fair assessment of the conditions
under which the image would have been created.
The difference you reported on the L* axis being a few points higher may be
traced to the G7 calibration method underlying SWOP2006. In my experience,
so far, it is clear that the latter causes midtones to print lighter than
their legacy TVI cousins. But that's MY very personal assessment.
I'm sure others will have lot's to write about SWOPv2 vs SWOP2006.
Roger Breton
> As most of you know, the default CMYK profile in the color settings of
> photoshop is U.S. Web Coated (SWOP)v2.icc. The profile on my machine
> is from 2000 and this has been the default as far back as I can
> remember. This is based on web printing on a #5 coated stock. As most
> of you also know, there is a much newer profile for web printing on a
> #5 stock called SWOP2006_Coated5v2.icc which is freely available at
> gracol.org. Would anybody like to expound on the differences between
> these 2 profiles? I'd love to hear it!
>
> I know that the new profile is based on averaged (massaged) data from
> a number of presses calibrated using G7 methodology and that the old
> one is based on presses set-up to the old SWOP TVI/density numbers,
> but that's about all I know. Where did Adobe get the old SWOP profile?
> Did anybody ever use it outside of photoshop? Does anybody know the
> "story" of that particular profile? On other lists there have been
> long debates (arguments) about how it turns certain blues purple and
> its many other shortcomings, but it must have had some validity to
> become the photoshop default... right? There are a number of
> differences I can spot easily in Colorthink, not the least of which is
> that the new profile is about 5x larger (2.6mb vs 550kb) and that it's
> gamut volume is about 4% larger, but there is some interesting/
> troubling behavior in photoshop that I'm hoping someone can shed some
> light on.
>
> Let's say (hypothetically) that I have an untagged CMYK image that I
> have no idea where it came from or what profile (it any) was used to
> make it, and I have no way of finding out, and yet I'd like to convert
> it to RGB to do some color work and then further convert it to a known
> good CMYK profile (such as SWOP2006_Coated3v2.icc) to proof and
> release. In the past when faced with this I generally had pretty good
> luck assigning the photoshop default (U.S. Web Coated (SWOP)v2) and
> then converting to my RGB working space. Today I was testing this
> workflow by assigning different CMYK profiles to my mystery CMYK image
> and looking at the resulting Lab values to see what was "going on",
> and that's when I really started to wonder about the differences
> between U.S. Web Coated (SWOP)v2 and SWOP2006_Coated5v2.
>
> Through most of the image there is not too much difference between the
> two, with the new one being about 2-3 points higher on the L axis. But
> when I get into the deep shadow, where image detail disappears into
> black, the old profile causes the image to plug up at a much lighter
> point and more "sharply". Here are a couple CMYK values and the
> resultant LABs so you can see what I mean. (Of course you can easily
> test this yourself).
>
> C, M, Y, K new SWOP Lab old SWOP Lab
> 46,51,59,82 17,4,5 14,4,7
> 58,57,63,90 10,3,3 5,2,4
> 68,63,62,94 6,2,1 1,1,2
>
> FYI, this image has a max ink limit of about 290%. The first value is
> somewhat typical of the bulk of the image, and the other 2 show how
> assigning the new profile leaves the deep shadows more open, with
> detail visible right up to the ink limit, while assigning the old
> value plugs up the detail at about 280%. This might seem minor, but it
> can have a huge effect on dark images, and I am just very curious why
> it does this. Did old SWOP presses plug up much easier than they do
> now? Is this just another example of how the old profile is "broken"?
> In ColorThink I can see that the A2B LUTs are about 13x bigger in the
> new profile - is there just not enough data in the LUTs of the old
> profile?
>
> Well, I could go on, but this is already a monster post so I'll leave
> it at that. Thanks in advance for your comments!
>
>
> Todd Shirley
> Urban Studio
> New York, NY
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