Re: Multi-color ICC profiles
Re: Multi-color ICC profiles
- Subject: Re: Multi-color ICC profiles
- From: G Mike Adams <email@hidden>
- Date: Wed, 23 Dec 2015 09:32:40 -0600
Mark,
> As Roger's OP was in reference to a printing press I assume he was
> referring to so-called 'hi-fi' printing on an offset litho printing press.
I’m not so sure of that. He really didn’t say. And since profiles beyond CMYK are more prevalent in large format printing than any other segment of the industry, that’s what I assumed when I read the initial post.
> I thought sending RGB files to these devices and letting the RIP
> handle the conversion was standard practice and the use of profiles for
> achieving predictable results had settled on a range of standards-based
> colour gamuts that reflected commonly used sets of 4-col offset printing
> conditions as their target(s). What use are multi-colour profiles outside
> of the RIP in this scenario?
That’s not exactly the scenario.
What a RIP does is convert pixel information, pixel by pixel, into dot information. So what a profile does is define to the RIP how the printer prints. The point of the profile isn’t to achieve some standard; it’s to recreate the actual color of each pixel in the incoming color space in the destination (printer profile) color space. Or, if a pixel’s color is out of the gamut of the destination space, to render as close a representation as possible.
These days, the main reason for beyond-CMYK inksets in general — and in large format in particular — is to be able — basically — to hit more Pantone colors. Not the only reason; there are still fine-art aqueous printers that use multi-channel mainly for photographic gamut, but the action the past several years has been in matching spot colors.
Best example is 021 Orange, or Home Depot Orange. You can’t get there with CMYK. Any CMYK. Add orange to the inkset, and you can. But when you do, you then have to profile to determine just how this inkset is printing. And you want to create dots accordingly. If the point of your profile was to align your printer with SWOP, or Gracol, or whatever, you’d be right back where you started, and you might as well not even have the orange.
But I do agree, except for soft proofing — which is possible but problematic in Photoshop — these profiles have basically no use outside of the RIP.
Mark,
>> I wouldn't say that multi-color profiling is something of a dying art.
Well don’t get me wrong. I love doing beyond-CMYK profiles. In fact, I love doing beyond-CMYK profiles with SepCntrl in Onyx on Canon iPFx400 printers — just about as intricate a profiling procedure as there is. As a profiler, I like to be able to take full control of every facet of how the printer prints in order to make the best possible use of all its capabilities in every environment on every media.
But how many people do that?
How many people profiling that machine do 7 color profiles, and how many just do RGB contone?
Also, maybe you’re not aware, but in your competitor Caldera, it’s not possible to make a more-than-CMYK profile. Regardless of the inkset, you create a CMYK profile, and the RIP does the conversion to the final actual colors. Not sure if the term is entirely right, but I think of that as ‘contoning’ the process…
and I hate it. Hate it so much that I argued with one guy at Caldera about it until I was nearly blue in the face. He seemed so completely obtuse about the entire issue that eventually I gave up.
Also of note is that in Onyx, while it is possible to use SepCntrl and create CMYKO profiles for the Epson SureColor, when you install them, they don’t work. The only way to profile these machines in Onyx is to let RIP ‘contone’ the orange split.
And I hate that just as much as I do in Caldera.
I’ve reported this twice as a bug, btw. Gotten nowhere. If you’re interested, feel free to contact me off list.
The above are all reasons it appears to me that multi-channel profiling is a dying art.
>
>> I'd classify it as a fairly tricky thing to do with some serious caveats
>> WRT V4 ICC profiles. Some of the challenges include:
>> 1. Dimensional complexity makes characterization challenging. You need
>> lots more patches to get good characterization. What works for 4 colors
>> becomes overwhelming for 7 colors.
Interestingly, while that’s no doubt theoretically true, my experience in the real word is that I get the best — by far — multi-channel profiles out of Monaco.
Amazingly small patch sets — particularly at 5 color — and I had hoped for better things out of i1P -- basically the Monaco engine and more patches.
But I’ve seen i1P fall down.
Monaco never does.
Mike Adams
Correct Color
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