Color theory defining the CMY primaries as substances that "absorbed" only one of the retinal primary colors: cyan absorbs only red (−R+G+B), magenta only green (+R−G+B), and yellow only blue violet (+R+G−B). It is important to add that the CMYK, or process, color printing is meant as an economical way of producing a wide range of colors for printing, but is deficient in reproducing certain colors, notably orange and slightly deficient in reproducing purples. A wider range of color can be obtained with the addition of other colors to the printing process, such as in Pantone's Hexachrome printing ink system (six colors),
Printing or building up many thin layers of material in succession. The technique is also known as additive manufacturing, rapid prototyping, or fabricating. Gang run printing is a method in which multiple printing projects are placed on a common paper sheet in an effort to reduce printing costs and paper waste. Gang runs are generally used with sheet-fed printing presses and CMYK process color jobs, which require four separate plates that are hung on the plate cylinder of the press. Printers use the term "gang run" or "gang" to describe the practice of placing many print projects on the same oversized