What to consider with fixed colour palette

This side-by-side comparison illustrates the brighter colours possible with expanded colour gamut printing.

In certain cases a fixed colour palette offers cost savings and enhanced store shelf appeal. Yet, it is not an all-encompassing solution to all problems printers are facing these days.


This article was written by Tom Polischuk

Colour is the pre-eminent element in graphic arts. It has been, is, and always will be in the unique possessive domain of artists. In the world of commercial printing, this means it resides with graphic artists and designers, along with the brand owners they represent.

Colour is also a science with a number of useful ways to characterise, measure and define it (e.g. wavelength, density, reflectance, hue angle, chroma). The science of colour – when applied by commercial printers – has one overarching goal: to provide for the accurate and consistent replication of the colour(s) selected by the graphic artists, over and over and over again, by the thousands and millions. This is no easy task, but colour science and the ability to “print to the numbers” are allowing this to happen.

For years and years (and still currently) the primary approach to achieve the desired colours in commercial printing has been to use 4-colour process CMYK (cyan, magenta, yellow, black) to produce colours within its gamut range and then supplement this by printing specific pre-mixed colours (spot colours) that were outside the gamut range or otherwise designated as a critical colour that was best achieved by pre-mixing pigments to an exact specification off-press.

CMYK + spot colour printing has been optimised and perfected over the years, but there are certain inefficiencies inherent in this approach. The most obvious is the need to treat each of the spot colours that a printer has to run as just what it is, a unique colour that must be set up on the press when it’s needed and removed when it’s not. This means more make-readies and more ink waste. This impacts printers directly and their brand owner customer indirectly in the form of higher costs and longer turnaround times.

A method that has gained much traction during the past 15 years or so is called expanded colour gamut (ECG; a.k.a., extended colour gamut, multi-colour separation) printing in which anywhere from one to three additional process colours are used with the traditional CMYK 4-colour process system to significantly expand the colour gamut that can be printed. As an example, one of the early commercial systems, Hexachrome, was a 6-colour system developed by Pantone Inc. (since acquired by X-Rite) in the mid-1990s that added orange and green to CMYK (designated CMYKOG).

With Hexachrome, printers were able to achieve about 90% of the industry-standard Pantone Matching System (PMS) spot colours, about twice as many as the standard CMYK system. Hexachrome also used fluorescent colorants in its 6-colour ink system to brighten the colours. Both Matt Furr, applications engineer for Esko, and Danny Rich, senior colour physicist for Sun Chemical, note that the fluorescent colorants made the system more expensive and more difficult to control for colour reproduction. Adding additional factors that made colour control more difficult was probably not a good idea, as most industry experts agree that  ECG printing requires a high level of control to achieve the desired results.

Multiple colour options

The industry has been hard at work since the early days of Hexachrome and today there are multiple colour combinations that are evolving for commercial use. Robb Frimming, print services director for Schawk!, lists several colour sets including, CMYKRGB, CMYKOGV, CMYKOGB, and CMYKOG. “These four are the most common in the work I deal with, and depending on many factors, the largest gamut volume can usually be achieved with CMYKOGV,” he says.

Catherine Haynes, technical solutions group for All Printing Resources, Inc. (APR), references a study performed by the Flexographic Technical Association (FTA) FQC committee in 2013 that compared several RGBOV pigments and potential gamuts. “Based on that study it was found the orange, green, and violet offered the largest gamut expansion. However, that is not to say that an expanded gamut ink set could not use blue in place of violet, or red in place of orange,” she notes.

According to Frimming, colour configurations typically come from three sources: the brand company, the printer, and industry specifications. “A brand company may decide on a set of ECG colours that can best represent their traditional set of spot colours,” he says. “In addition, other production configurations can include CMYK and extra colours that address a very specific brand need, but are not traditional ECG process colours.”

Printers can also select a set of ECG colours that best meets their customers’ needs and run these exclusively on all their presses. “If a client set and a printer set conflict, then decisions need to be made on how to proceed,” says Frimming.

The third source for colour configurations can come from industry specifications. At the FTA Fall Conference held in Minneapolis, MN in October, Mark Mazur, digital prepress consultant for DuPont and chairman of the FIRST Leadership Team, presented the latest update to FTA’s FIRST (Flexographic Image Reproduction Specifications and Tolerances) specification, designated FIRST 5.0. This version includes standards for ECG printing in terms of hue angles for CMYKOGV inks “in an attempt to give brand companies and printers a starting point for ECG initiatives,” says Frimming, co-chairman of FIRST Leadership Team. The established hue angles are: C, 233 degrees; M, 357; Y, 93; O, 54; G, 181, and V, 307.

Eyes wide open

The starting point for a printer when considering ECG printing comes well before the selection of the right combination of colours. ECG printing is relatively new and evolving and it requires that printers know what they are trying to accomplish and what level of commitment is needed. “First, it is important to have a clear understanding as to why you want to move this direction,” says Haynes. “Is it driven by a customer or to optimise a new press or to gain new business? To really maximise on some of the economic benefits ECG offers, it is ideal to have a clear path for implementation and to have sufficient work and jobs to dedicate to the technique. This also requires a clear communication path with customers and/or potential customers as to their interest and commitment to ECG.”

Having the customer base that allows a printer to dedicate a press to ECG is an important consideration, says Furr. “The idea behind ECG is to eliminate the traditional CMYK and spot colour printing where you are constantly changing out tooling and inks in the press,” he says. “So one of the top considerations is: ‘Do we have the customer base to make it worthwhile dedicating a press to ECG?’”

Scott Hosa, director, graphic technology for design/branding firm Landor Associates, expands on this point. “Efficiency and cost savings from ECG printing are derived from reduced changeover time between jobs, the ability to gang up multiple items on a forme, quicker make-ready, smaller ink inventory, bulk ink purchasing, and reduced demand for spot ink formulation. In order to realise these efficiencies, all or most of the work must be formatted ECG. Having to ‘break-in’ to back-to-back ECG jobs for spot colour work is counter productive to that strategy.”

Clearly, a high degree of collaboration is needed for the successful implementation of ECG printing. This includes all the key stakeholders from CPCs/brand owners, designers, separators, and printers. Creating realistic expectations on the accuracy of spot colour matching is a critical part of this, along with education of personnel throughout. Marc Welch, director of strategic accounts, GMG Americas, says that successful implementation of ECG requires “significant re-education of prepress and pressroom personnel, along with education of sales and clients on proper expectations for ECG. In some brands that have a commitment to ECG, design people are being educated on how to create optimal artwork for the technique.”

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