Special inks have been used to enhance printed pages for many years. They provide additional colours that are either out of a CMYK gamut, or that are difficult to achieve within it. The best-known provider of special colours is Pantone, now owned by X-Rite, and the Pantone Matching System (PMS) is one of the industry's enduring constants. Pantone GOE, introduced a couple of years ago, is a streamlined and enhanced ink-set that has over 2,000 additional colours for printing as either spots, in CMYK, or rendering in sRGB and HTML. The idea with GOE is to fill in the gaps missing in the PMS and to make it easier to reproduce colours on press and on digital media.
The addition of spot colours to a four-colour run on a multi-unit press is common enough. Spot colours can be colour managed and controlled much the same as CMYK, although ISO 1264-2 makes no provision for the tolerances of spot colours. However the need to increase print's competitiveness with other media, and to exploit press technology advances fully, is encouraging designers and print buyers to be bolder in their designs. Market forces and the need for print to compete with alternative media are part of the reason for more exotic special effects inks being used in different applications. It is possible to create special effects with PMS and GOE inks, but far more dramatic results come with the use of fluorescents, pearlescents, metallics and similar speciality inks.
Such inks have mainly been used in packaging and clothing print, where they offer designers many more exciting possibilities than simple PMS or GOE options. Designers can extend the colour pallet to include fluorescent, pearlescent and metallic effects and ever wilder creations. Thermochromic inks for example react to heat, and are commonly used in novelty tat such as mugs that change colour when you add hot water. A more serious use is in smart packaging where thermochromics are used to show when the correct temperature for something, such as food products, has been reached. The world market for smart packaging will supposedly grow to be worth $14.1bn (￡8.9bn) in 2013 according to a report from NanoMarkets, a research outfit.
And then there are the photochromic inks that change colour under certain types of light and are used in security printing applications. Hydrochromic inks change colour when wet, which is rather fun for umbrellas or bikinis, and glow in the dark varieties, or those that are only visible under UV black light, and there are even inks to create a distressed or antiqued look. International Coating has developed the wonderfully named Destructo White which is used to create distressed effects on clothing. Once printed and cured the garment is stretched so that the ink cracks and flakes off. This is probably not the design goal for most special effect inks.
Complex special effects created using colour and physical behaviours create excitement and engagement for the consumer, helping build brand loyalty. They can become intrinsic to the product. For example the special icy metallic effect ink Coca-Cola uses is associated with its Zero branding (Coke Zero, Sprite Zero). But special effect inks are not just about novelty and brands. In food packaging, security printing and pharmaceuticals they play an important role in protecting consumers against fraud.
A key difference between specials and special effect inks is cost and performance. The cost of a litre of ink depends on the amount purchased, the ink's characteristics and its overall quality. In 2007 a legal case established that the ink in a desktop printing cartridge costs nearly $2,000 (￡1,270) per litre. Last May Flint Ink announced a rise in its sheet-fed inks prices of six percent and that heatset inks would rise by €0.30 (19p) and coldset by €0.25 (16p), depending on the specific product. The choice of ink will also depend on how it behaves on press. For printers who want to keep their presses running at 18,000 sheets per hour (sph), an ink that requires the press to slow down to 15,000sph has an added cost on top of the ink's price.
The best-known names in ink manufacture are Flint Group and Sun Chemical, both of which offer metallic and fluorescent inks, and Fujifilm Sericol. Most ink technology innovations are expected to be in ink-jet inks, because this is the part of the market growing most energetically.