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),
Blue–green distinction in language in Amazigh language is "Azerwal". In some dialects of Amazigh, like Shilha, the word "Azegzaw" is used for both green and blue. The color of the sky is sometimes referred to as "the green" in Classical Arabic poetry, in which it is al-khaḍrā' (). In Arabic the word for blue is generally "azraq" (). The Arabic word for green is "akhḍar" (). In Moroccan Arabic, the word for light blue is "šíbi", whereas "zraq" () stands for blue and "khḍar" () for green. The word "zrag" () is used to describe the color of a suffocated person, and is also