Idealliance Releases XCMYK Expanded Gamut Dataset

Friday, December 02, 2016

Press release from the issuing company

XCMYK is a four-color printing method, a dataset, and an ICC Profile.

Alexandria, Va. - Idealliance, the industry association representing all facets of the global media supply chain, has released a new dataset and profiles supporting XCMYK four-color expanded gamut printing. After 26 international test runs over 15 months, Idealliance has released the XCMYK profile and announced XCMYK, a new colorspace representing XCMYK expanded gamut printing that can be achieved on offset and digital devices.

The XCMYK dataset and profiles can reproduce a larger gamut than that of GRACoL^®, the industry’s current standard for print quality. The XCMYK dataset and profiles can also be used directly in digital front ends for presses, proofers, and other devices. Profiles can be used on traditional four-color presses as well as on a variety of digital devices to produce a colorspace larger than current traditional printing.

“GRACoL continues to meet the quality needs of the majority of printing today, but many devices can now print to a larger colorspace,” says Tim Baechle, Idealliance Director of Global Print Media Markets and Technologies. “Because of this, Idealliance and its GRACoLWorking Group sought to develop a colorspace for the future that can be used both by digital devices as well as traditional offset presses.”

The output space of XCMYK represents an expanded gamut based on 26 dedicated pressruns conducted on offset presses using standard IS0 12647-2 compliant inks and non-traditional (e.g., FM) screening, as well as a wide variety of digital devices. The project was overseen by the GRACoL Working Group and a special task force of more than 100 professionals from 88 companies, and conducted over a 15-month period in 2015-16 involving test runs from all over the world, including Hong Kong, China, Singapore, Malaysia, Pakistan, Canada, and the United States.

The XCMYK project involved significant contributions of pressruns, time, labor, and raw materials from printers, manufacturers, and Idealliance volunteers, with total time and raw materials estimated at more than $350,000.

XCMYK Expanded Gamut printing represents just one part in a series of Idealliance expanded gamut initiatives. The Idealliance Print Properties and Colorimetric Council and GRACoL Working Group is conducting a traditional expanded color gamut (CMYK+OGV) research and education project, with details to be announced in the coming weeks.

With the introduction of XCMYK, Idealliance is making profiles, datasets, and basic information about calibration and profile use available. To learn more about XCMYK or to download the profiles, datasets, and other information, go to www.gracol.org or contact Tim Baechle at [email protected] or (703) 837-1069.

Discussion

By Gordon Pritchard on Dec 02, 2016

It looks like they decided to go for maximum gamut - i.e. 20 micron FM screening, high SIDs in addition to the extra colors. I wonder if that's a very practical approach.

Interesting (and odd) that the C and M SIDs are the same (C: 1.85 M: 1.85)

The XCMYK test form they show in their introduction appears to be 4/C rather than 4/C +?

They also chose RGB as the extra colors rather than OGV that's used in, for example, Pantone's EG system. Why those RGB colors?

There's no mention of ink sequence.

So many questions....

By Gordon Pritchard on Dec 02, 2016

My mistake - it's just 4/c not 4/c plus.

By Barry Brown on Dec 09, 2016

I always have wondered a bit about CMYK+RGB. For example, solid areas in the red separation would be overprinting red areas produced by solid magenta and solid yellow. I think, that the luminance of those reds are degraded by those overlaying ink films, so that the colour space is nnot really expanded that direction. (The same would be the case in the solid greens and solid blue's.) I really can't see that CMYK+RGB truly expands the colour gamut, because some colours are at the same time being impinged.

CMYK+OGV,on the other hand, does allow narrow-band color separations, and solid-over-solid overprinting is not an issue.

I was always a fan of the old CMYK+CMY(K) method (which Crosfield's Tony Johnson called Hypercolour). CMYK+CMY(K) allows one to run the press at standard ink densities, just putting the paper through the press twice.
Benefits: No need for extra press units, no need to clean ink ducts, no need to change press settings.
The CMYK separations are best made 'achromatic', 'polychromatic /PCR', or grey-component-replacement/GCR (depending on who's terminology one uses), ie. the separation of the full-range black is such that the 'grey' component of quarter-tone through to shadow-tone colours is made-up mostly by two ink colours plus black.
The subsequent CMY (and optional second K) are separated with maximum Undercolour Removal /UCR, so those separations look pretty skeletal. They are there to add to the SID of the first print-run, so whereas the SID of C could have been 1,85, after the second print run it might be 2,30; M & Y equally incremented.
In my experience that really expands the colour space.
Some of the best CMYK+CMY printing that I've seen was done by the Helsinki printer Erweko, but that was many years ago now.

By Gordon Pritchard on Dec 09, 2016

Running CMYK at higher ink densities than standard (whether single hit or two hits) increases gamut due to higer saturation but does not make up for gamut issues related to ink hue and over prints. I.e. with CMYK you'll not achieve the oranges possible by using a, for example, PMS 021.
The issue with CMYK+CMYK is overcoming registration issues caused by running the substrate through the press twice. There's also the cost associated with running the same job twice. It's more efficient/effective to run the job once with inks at higher SIDs. There is a limit as to how high you can run the SIDs while increasing saturation and that is reached when the chromatic colors are about 35 points above standard.
The idea is not new. E.g. I did a blog post in 2009 ( http://the-print-guide.blogspot.ca/2009/01/printing-at-dmaxx-maximizing-cmyk-gamut.html ) about the method I developed and used at Creo in 1999. We called it DMaxx for Density Maximum.
What I'm concerned about is the initiative to formalize this method as an industry standard or specification especially using FM screening (you can do high SID printing with AM/XM screening)