The Hard Problem of Expanded Gamut Printing

 

Expanded gamut is the buzz of the year, with endless discussions of the fine technical points of EG printing; but in the flurry of details, we may be ignoring the hard problem of expanded gamut printing: consistent process control.

Expanded gamut, or N-color printing is hot right now, though it isn’t really that new. A major push towards expanded gamut took place in the mid ‘90’s and earlier; and it can be argued that the “K” in CMYK was already an “N” color back in the earliest day: a hi-fi gamut expander for the deficient blacks in the original CMY color process.

The path towards true HiFi color is littered with failed attempts, and all sorts of explanations have been offered for the failures: “The gamut increase wasn’t that great,” “We get a bigger punch with a bump plate,” “Customers should be willing to pay for it,”  “It never really worked for us,” “The workflows are too complicated,” “I don’t know how to proof it.” And so on.

But every once in a blue moon we hear what is probably the most likely and honest explination for expanded gamut failure: “We just couldn’t control the process,” And I think that’s about right.

Nearly every expanded gamut solution that has been tested has shown good, and even excellent results…in the lab; but results in the field have not always been as successful.

Let’s make a quick listing (in no particular order) of a few of the leading EG contenders over the years:

  1. High density CMYK…just put more ink on the sheets. (Notably in flexo through the use of advanced plate technology).
  2. CMYK Max, or CMYK-CMYK..use a second hit of the primary colors for added punch.
  3. High Chroma Inks…use better quality inks (and ideally, papers) to achieve a higher chroma than standard inks can provide.
  4. FM screening…solid primaries will stay the same but screened areas will gain in vividness and clarity.
  5. N-Color…CMYK+RGB or CMYK+OGV or 6 color variations of the same approach…punch the color gamut out in the overprint areas where CMY combinations are weakest.
  6. Proprietary Systems…Various custom solutions supported by a number of graphic arts companies that specialize in color.
  7. The combination approach…multiple techniques may be combined for maximum results: High chroma inks+high densities+CMYKOGB+FM screening would seem to be the “all stops pulled out” approach.

One thing that most of these systems have in common is that they can produce remarkable results when implemented properly. The other thing that many of them have in common is that they too often fail to deliver the desired results “in the trenches,” Printers often find that they cannot rely on expanded gamut print to perform as expected, despite the proven excellence of the system in test conditions.

So what’s the problem?

Clearly the problem is not with the systems themselves, which are all capable of delivering results that range from “Pretty Good” to “Wow!!” but rather with the printers themselves, who are often not prepared for the increased process control demands required for success in expanded gamut printing.

In a sense, expanded gamut printing presents a perfect storm situation for printers, with higher expectations for quality combined with a process that may be more difficult to control than conventional CMYK printing. Let’s take a closer look at some of these factors:

  1. Raised expectations: Clients who anticipate improved quality through expanded gamut printing are disappointed when the results fail to sizzle. Printing that would have been acceptable as conventional CMYK is a letdown in EG.
  2. Tighter tolerances: Expanded gamut is coming into increased use in the packaging arena, where color tolerances can be tighter than in commercial printing. Logo colors, brand colors, custom colors and PMS matches are often specified in deltaE tolerances that could be considered unrealistic in much commercial printing.
  3. More variables: It’s easy to appreciate the fact that, for example, CMYKRGB printing, one popular form of expanded gamut printing, has more colors than CMYK printing-three more, to be exact; and that represents more things for the press operator to control, and more things to potentially go wrong.
  4. More complexity: This is related to point three, but in a slightly different way. A single solid spot color is controlled mainly by just three factors: the color of a single ink, the color of the paper and the density of that ink on press. When a solid spot color is simulated in an expanded gamut scenario, several different inks may be involved, and not just solids, but solids and tints together. The complexity can be orders of magnitude higher.
  5. Lack of preparedness: Many printers have been able to “get by” in CMYK or CMYK + spot printing for years with minimal process controls in place, guided by a good eye and fast seat-of-the-pants reactions. That approach never had a chance of working in expanded gamut printing.

So, given all the challenges to expanded gamut printing, what process control factors need to be controlled to master expanded gamut?

  1. Tight control over all primary colors. This would mean not only CMYK, but also, depending on the system being used, CMYKcmyk, CMYKOGB, CMYK RGB, CMYKOG, etc.  And the control of all the colors has to be colorimetric, not only density-based.
  2. Tight control over dot gain, including supplementary colors. TVI is far too often ignored in CMYK, and almost universally ignored in spot color printing, where the only concern is with the 100% solids. In expanded gamut printing, where most of the brand colors will involve tints of both CMYK and the additional colors, accurate TVI control is a must.
  3. Communication between press and prep. Plates and plate curves have such a strong effect on TVI that constant communication is needed from press to prep to assure that the press operators are getting the plates that will enable them to hit the mark consistently.
  4. A culture of consistency. The old habits of improvisation don’t go away by themselves. After years or even decades of running each job a little differently to get an eyeball match, many press operators are unprepared to strive to run consistently every time, and may even be unaware that it is a desirable goal. In order to succeed with expanded gamut, the values, software and equipment to do so must be firmly in place and used on every job.

Expanded gamut printing is an exciting development, and many of the required pieces are beginning to fall into place: sophisticated color management systems, efficient workflows, accurate proofing systems, advanced plating technology and exotic screening systems. But all of it relies on a foundation of accurate and consistent process control. That is the hard problem of expanded gamut printing.

I always keep my posts informative and product promotion-free. If you are a buyer, brand owner or printer interested in the subject of color communication, please check out my other posts and browse my website for more information on achieving effective prep-press collaboration. If you would like to learn more about process control and brand color verification with pressSIGN, please click here. Or contact me directly at glenn@colorclarity.net

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2 Responses to The Hard Problem of Expanded Gamut Printing

  1. John Sweeney says:

    In the packaging market, the great opportunity is matching a larger number of spot / brand colors – without having to change inks. For example, multiple SKU’s run on a flexo label job, offers significant savings in manufacturing (few plates, no ink changes)

    I echo Glenn that process control is key – and the good news is closed-loop color for flexo presses is coming – (AVT, eltromat, Techkon, GraphiKontrol).

  2. Pingback: The Hard Problem of Expanded Gamut Printing - Printing Impressions

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