Inking Outside the CMYK Realm

A look at two ink systems for HiFi printing.

By Terri McConnell, Prepress Editor

"IN 1903, THE Wright brothers made their first engine-powered flight. Sixty-six years later, we put men on the moon. If you compare the evolution of flight to the evolution of color in print, we're still in the dark ages. Four printing plates and four cans of ink." So begins Matthew Bernasconi's call for a revolution in ink.

Bernasconi, founder of the Australian company Opaltone Graphic Solutions, is a passionate evangelist for what is known as HiFi printing—the use of a six- or seven-color ink system to replace the four-color (cyan, magenta, yellow, and black) system that has been our basic recipe for image reproduction since it was invented in 1859.

The most well-known of the HiFi printing ink systems was developed and patented in 1995 by Pantone, the 40-year old company that brought us the ubiquitous Pantone Matching System (PMS). For years, CEO Richard Herbert worked with Pantone's color scientists to devise an expanded ink system capable of accurately reproducing more of the design colors found in PMS swatch books than could be reproduced with the CMYK ink system. They eventually settled on a six-color system that Herbert named Hexachrome. The Hexachrome ink set is comprised of black, orange, green, and re-formulations of process cyan, magenta, and yellow.

Says Amy Fannon, technical project manager, "The best way to see the impact of Hexachrome is to look at the books." She's referring to Pantone's Solid-to-Process and Solid-to-Hexachrome Guides. According to Fannon, printers can expect to match fewer than 50% of PMS colors using standard CMYK inks. With Hexachrome inks, they can accurately simulate over 90% of the colors found in the PMS swatch books.

Fannon, and her colleague Ken Wagner, are key members of Pantone's Hexachrome product development and technical support team and are currently heavily focused on bringing the message of HiFi printing to the label and packaging markets. Our industry is ripe with presses—both offset and flexo—with six, eight, and ten print stations. Wagner says there are distinct economic advantages for running Hexachrome on these presses when the system is adopted as a mainstream process rather than as a novelty. Because of the increased color gamut of the six-color system, color match can be achieved without using special spot color inks on a wider range of jobs. No special inks means fewer wash ups and more opportunities to gang up shorter run jobs on the same substrate. (Note: Hexachrome Magenta ink is more expensive than standard magenta because it's made with rhodamine pigment rather than rubine.)

"Reducing wash downs is a big cost savings for printers," claims Wagner. "But there's also economies in file preparation. Normally, you have to isolate spot color areas from process areas. Not with Hexachrome. Our plug-in software programs have easy conversions from RGB, CMYK, or LAB color spaces into the Hexachrome color space."

According to Wagner and Fannon, the Hexachrome system is fully ICC aware, and files can be passed back and forth between any users with editing programs that support multi-channel separations. The company markets Hexware plug-ins for desktop editors like Photoshop and Illustrator. High-end system manufacturers like Barco, Agfa, and Creo support Hexachrome files with special color look-up libraries. Profiling is accomplished with third-party calibration products like Monaco, Gretag, and Color Blind that are licensed to make Hexachrome profiles.

Pantone openly recommends an RGB workflow for Hexachrome users. Says Fannon, "The RGB workflow is becoming more and more accepted because of its efficiencies: wider color gamut, smaller file size, easier to achieve color, and less color correction because you're in that wider space. Also, there are more Photoshop tools in the RGB space than in CMYK. CMYK is a device-dependent color space, so for example, blacks and gray balances are generated specifically. With RGB it's easier to re-purpose files (for the Web, for example) because files are not output-device dependent."

If six inks are good, could

seven inks be better?

Bernasconi disagrees that it's necessary to adopt an RGB workflow in order to print HiFi color. His Opaltone method differs fundamentally from Pantone's method in that it uses seven ink colors rather than six, and it is based on an "enhanced" rather than a "modified" CMYK process.

He says Opaltone was inspired by a scanning experiment in which he used a two-pass process to increase the color range of an image—he would scan for CMYK in one pass, and then scan a second time for RGB saturation. Encouraged by the results, he studied the work of Harold Kuppers, who wrote a patent in the early seventies on seven-color printing. "The difference between his patent and mine is that he actually replaced secondary colors in the image, similar to a Hexachrome system," explains Bernasconi. "I had decided that wasn't the major deficiency in the process. The main deficiency was saturation, or getting that 'layering' of the color."

Consequently, the Opaltone process doesn't alter basic CMYK data. "We're simply adding on the saturation data that's missing through the tone compression of the first scan, or the first CMYK data range. Imagine that CMYK is your first coat of paint. Opaltone is like going over that base image with a second coat of paint for increased saturation."

Though introduced in 1996, Opaltone remained a relatively unknown process until March 2000 when the company released its Opaltone Matching System (OMS) Color Books, which feature some 2,880 colors in three volumes. In February 2000, Bernasconi signed a distributor agreement with Harper Corporation of America, the Charlotte, NC based anilox roll manufacturer, to sell Opaltone in North and South America. Says Bernasconi, "Our success in getting Opaltone into the market is really predicated on getting the inks on press and doing a print trial." To that end, Harper, with Bernasconi's ongoing support, is busy lining up demonstrations and public exposure for the seven-color ink system.

For more information on HiFi printing, contact: Fannon at afannon@pantone.com, or Bernasconi at matthewb@opaltone.com.