Extended Gamut
Most people are aware that you can make many colors by mixing other colors. Our color televisions use Red, Green, and Blue; that is why we often hear them referred to as RGB. These are the additive color primaries that when blended together in various ways can produce a broad array of shades. The additive primaries refer to actual light as it is received by our eyes. When all three are added together we produce white light.
In printing, including inkjet printing, the process colors used are Cyan, Magenta, Yellow and Black or CMYK. When Cyan, Magenta, and Yellow are blended in the correct amounts we get close to black. Our pigments aren't perfect so we also use actual black along with the three subtractive primaries. With subtractive colors light is absorbed at some wavelengths and reflected at others. For example, when we mix Cyan and Magenta we get Blue where white light is mostly absorbed except for the blue wavelengths.
The subtractive primaries allow you to achieve other colors, however they only cover a limited area of the color space. In commercial printing printers use what are called spot colors to overcome the limitations of CMYK. in inkjet printing, until very recently there were few solutions.
An example of the limitations of the CMYK subtraction model is that oranges are created by mixing Y yellow and M magenta. This results in a dirty, grey-shade orange. Ask any photographer about the pain of seeing their reds looking as if a little black was added. In effect the subtractive primaries are not very good at producing the additive primaries. Red, Greens, and Blues lack the saturation (Chroma) that is sometimes needed.
By adding Red, Green, Blue, and Orange to our standard CMYK ink set we allow digital prints to produce colors that were impossible to reach before. Bright, clean reds, warm oranges and pinks with high saturation.
The extended gamut ink set is especially useful for the production of color proofs and posters.
