There are billions of monitors worldwide that can reproduce the exact same color when instructed to. This engineering marvel only works because of a standard definition for colors. Earlier, colors were loosely defined using limited words—most languages have at most twelve color terms. These loose definitions work for general use but lack precision for subtle differences between similar colors.

The same color label like 'green' can describe vastly different shades. While terms like lime-green or olive-green create distinction, this naming system is clunky and inefficient. Instead of mapping colors to millions of labels, numbered units provide better precision through digit count.

Colors can be physically measured through light—composed of photons with specific wavelengths or frequencies. By measuring intensity per wavelength, light is represented as spectral power distribution. This quantification explains why hex codes have limitations (16,777,216 values) and addresses phenomena like the 'dress' color debate and color blindness.