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: Sat, 05 Jan 2008 13:36:24 -0500
Todd,
I feel your pain being caught into an "anti-color management group". It's
true that people often don't want to hear the very words color management
and ICC profiles pronounced together in the same sentence because that makes
them sick. There has been many disapointments over the years with regards
to CMS, for good or bad. With the results that, understandably, users have
become extremely cautious when it comes to move away from AdobeRGB and
SWOPv2. So where do you want to go from here, if you're so bold to want to
take color in your hand in your company? You come to this list, of course.
> Roger, you hit on the hidden agenda of my original post, which is
> strategies for assigning profiles to untagged CMYK images. Although it
> won't work in all cases, assigning SWOPv2 is usually a decent place to
> start, simply because it is the photoshop default. That being said, I
> was trying to figure out what was going on in the shadows of some
> untagged cmyk images when I assigned SWOPv2. After further
> experimentation, I think the main thing to be learned is that plugging
> up shadow detail is a good indicator that I'm not assigning the right
> profile! Any other pointers or tricks that you know of?
Keep in mind that many images you'll stumble upon were'nt necessarily
separated for printing on a web press and so, it's very possible that you
will encounter 320% and 340% total ink limit. If all you have to interpret
those ink combinations that are valid on a good sheetfed press is SWOPv2
then you may be drawn to conclude that all that shadow details is going to
get squashed.
> The thing I find interesting/confusing is how the same CMYK values can
> have such significantly different LAB values when comparing U.S. Web
> Coated (SWOP)v2 to SWOP2006_Coated5v2.
Doesn't that make life more interesting?
> Roger mentioned that the old
> SWOP is based on the CGATS TR-001 1995 dataset. Does that data really
> plug up so badly in the shadows? And if so, why? I mean really, has
> web offset technology really advanced that much in 10 years? Why would
> TR-001 be so much different from the 2006 datasets? Even given the
> differences between the G7 methodology and the old TVI/density process
> control, I would think that the presses behave fundamentally the same
> as they did back then.
Again, consider the source of your separations. If you open an image
separated for 300% total ink limit, will you be drawn to the same
conclusions? My point is, if you study the TR-001 data, I don't think you'll
discover that they had poor print contrast back then, in 1995, when they
they conducted that historic press test. That's easy to do if you have
access to the spectral flavor of TR-001 dataset because you can lookup for
yourself the densities for the 75% dot (yes, dots! I hope that's not taboo
anymore) to calculate Print Contrast and decide for yourself whether they
were printing "plugged-up" in those days -- the same cannot be said, of
course, for the current's SWOP2006 or GRACoL2006 or Fogra39L or Fogra40
datasets, because, by the time those fancy smoothing algorithms are done
with the data, wherever the raw data came from, all spectral information is
gone out of the measurements and it's no longer possible to determine old,
antiquated things like dot gain and print contrast! Things that could help
shed some lights on your legitimate burning questions.
> In fact I am only interested in the colorimetric rendering intent, but
> I'm wondering does this even apply when you just ASSIGN a profile? I'm
> not actually converting, so does the rendering intent matter? If so, I
> would assume it is what set in the color settings?
When viewing CMYK images in Photoshop, Todd, it does not matter which RI is
selected in ColorSettings as everyone on this List knows that Photoshop
strictly uses the RelCol tag for display. The Lab readout in the Info
palette, though, is another story.
> .... Just for the
> edification of everyone here, where exactly can we find detailed
> information about the ISO paper classifications?
ISO-12647-2.
> Thanks again to everyone who responded!
>
> -Todd Shirley
> Urban Studio
> New York, NY
Roger Breton
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