CMYK color model spot colors (such as metallic inks), and finishes such as varnish, which enhances the glossy appearance of the printed piece. CMYK are the process printers which often have a relatively small color gamut. Processes such as Pantone's proprietary six-color (CMYKOG) Hexachrome considerably expand the gamut. Light, saturated colors often cannot be created with CMYK, and light colors in general may make visible the halftone pattern. Using a CcMmYK process, with the addition of light cyan and magenta inks to CMYK, can solve these problems, and such a process is used by many inkjet printers, including desktop models. Comparisons between RGB
Magenta colors of pigment. (The secondary colors of pigment are blue, green, and red.) As such, the hue magenta is the complement of green: magenta pigments absorb green light; thus magenta and green are opposite colors. The CMYK printing process was invented in the 1890s, when newspapers began to publish color comic strips. Process magenta is not an RGB color, and there is no fixed conversion from CMYK primaries to RGB. Different formulations are used for printer's ink, so there may be variations in the printed color that is pure magenta ink. A typical formulation of "process magenta" is shown in