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 for each of blue (""), green ("") and grey (""). For all three, different shades can be indicated with different (compound) terms, none of them being considered as basic color terms: "bleu " (light blue), "bleu " (sky blue), "bleu " (Navy blue), "bleu " (royal blue); "vert clair" (light green), "vert " (literally: apple green); "gris " (very dark grey), "gris " (literally: mouse grey). French also uses "" for the lighter shade of blue of the sunny sky, that was in turn loaned to English as "azure". Catalan distinguishes blue (') from green (') and grey ('). Other