CMYK: The four process colors (cyan, magenta, yellow, black) will not reproduce as large a color gamut as RGB. In theory 100% each of cyan, magenta and yellow should create black but because of ink impurities this combination will yield a muddy brown. Black ink is required in order to produce a true black as well as add depth and detail. Cyan is contaminated with magenta and yellow so slightly higher percentages of cyan must be used in combination with magenta and yellow to create neutral 4-color grays.
Duotones: Typically a light ink is used for highlight to midtone areas and a dark ink for midtone to shadow areas. The light ink will have the sharpest contrast below 40%; the dark ink above 50%. A second application of the same ink will create deeper, richer color in the 3/4-tone and shadow areas. Duotones cannot be proofed accurately, so press proofs are recommended for critical work.
Fluorescent Inks: Semi-transparent, these inks can be overprinted to create color mixtures, but may require several passes through the press. White stock is recommended for maximum brilliance. Caution: Fluorescent inks are not as fade resistant as standard inks.
Hexachrome Inks: Developed by Pantone, Inc., the Hexachrome system is comprised of six colors: CMYK plus orange and green. Over 90% of the Pantone Matching System (PMS) colors can be reproduced with the six Hexachrome inks. Used primarily by packaging printers.
Metallic Inks: These inks work best on smooth, coated stocks. Because metallics are opaque they require special trapping considerations. Cautions: metallic inks are more difficult to run and have less abrasion resistance than conventional inks. Metallic inks are considerably duller on uncoated papers, and varnishes will dull metallic colors.
Pantone® Matching System (PMS): Over 1,000 colors can be specified from this system including pastels, neons, and metallics. Use the Pantone Bridge Colors when converting PMS colors to CMYK to predict how the color will print when converted to process.
Toyo® Color Finder System: Ink matching system from Toyo Ink Manufacturing Company of Japan. Toyo makes various process inks, spot colors, and varnishes. MGTL uses Toyo vegetable-based, solvent-free inks.
Trumatch®: Matching system for selecting colors based on CMYK mixtures. Trumatch does not make ink, just swatch books showing various combinations of colors made from process along with their CMYK percentages.
Ultraviolet (UV): Inks designed to dry almost instantly when exposed to an ultraviolet light source.