Modeling of the discrete RGB digital color space to the visible color spectrum

<ns3:p> The author asks a basic question: how does the world of color work, and how does a continuous physical spectrum become a perceived hue. This perspective is then contrasted with digital practice, where colors are encoded discretely as RGB triplets and reproduced by displays that emit artificial light with device-specific spectral characteristics. The article examines whether a conversion from digital colors to a physical, wavelength-based description is possible, and whether such a conversion is meaningful. By considering metamerism, inter-device variability, viewing conditions, and observer-dependent perception, the author argues that assigning an RGB value to a single "true spectrum" is inherently non-unique and only weakly justified from a perceptual standpoint. A further conclusion is practical but important: even the finite RGB space is beyond direct human comprehension. Not all differences between RGB codes are perceptually discriminable, and even when they are, discrimination does not imply that people can reliably assign unique names to every visible difference. In effect, the infinite spectral domain is reduced to a finite set of digital RGB codes and then reduced again to an even smaller set of linguistic color categories. Building on this, the paper proposes heuristics that are sufficient for precise everyday use of color terminology, while acknowledging their heuristic nature: (1) an author-defined RGB color cube with vector-based region assignment for named colors, (2) quantitative sampling with a nearest labeled neighbor rule, and (3) data-driven classification on the sampled datasets, including supervised models and clustering methods. </ns3:p>