RYB color model 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, for the widest range of high-chroma colors. RYB (red–yellow–blue) make up the primary color triad in a standard artist's color wheel. The secondary colors purple–orange–green (sometimes called violet–orange–green) make up another triad. Triads are formed by three equidistant
Returns to scale (DRS). If output increases by more than the proportional change in all inputs, there are increasing returns to scale (IRS). A firm's production function could exhibit different types of returns to scale in different ranges of output. Typically, there could be increasing returns at relatively low output levels, decreasing returns at relatively high output levels, and constant returns at one output level between those ranges. In mainstream microeconomics, the returns to scale faced by a firm are purely technologically imposed and are not influenced by economic decisions or by market conditions (i.e., conclusions about returns to scale are derived from