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),
Natural Color System more colors (184 light colors and 16 in the blue-green space) were added, adding to the current 1950 colors in the NCS 1950 standard colors. Colors that have a representation in the NCS 1950 samples are denoted with a leading capital "S", for example NCS S 1070-Y10R (a chromatic, slightly reddish yellow). The most important difference between NCS and most other color systems resides in their starting points. The aim of NCS is to define colors from their visual appearance, as they are experienced by human consciousness. Other color models, such as CMYK and RGB, are based on an understanding