RYB color model as the "three" psychological primaries, with black and white occasionally added as a fourth and fifth. The cyan, magenta, and yellow primary colors associated with CMYK printing are sometimes known as "process blue", "process red" and "process yellow". RYB color model RYB (an abbreviation of red–yellow–blue) is a historical set of colors used in subtractive color mixing and is one commonly used set of primary colors. It is primarily used in art and design education, particularly painting. RYB predates modern scientific color theory, which has determined that cyan, magenta, and yellow are the best set of three colorants to combine,
Early American editions of The Hobbit 14th impressions come in a variety of colors. Generally all the books from one printing are bound in the same color, but exceptions may have been found, perhaps when bindings intended for one printing were left over and found use at the beginning of the next printing. Hence the color of the covers cannot conclusively identify a book. The 6th impression's blue-green is medium light and distinctly blue. The 7th impression's khaki binding, on the other hand, shows no hint of blue or green. Its color is considerably darker than the 10th through 12th impressions. The rust color of the