Лако-красочные материалы — производство

It is commonly stated that there are fifteen specific causes of colour, arising from a variety of physical and chemical mechanisms. These mech­anisms may be collected into five groups.

(a) Colour from simple excitations: colour from gas excitation (e. g. vapour lamps, neon signs), and colour from vibrations and rota­tions (e. g. ice, halogens);

(b) colour from ligand field effects: colour from transition metal com­pounds and from transition metal impurities;

(c) colour from molecular orbitals: colour from organic compounds and from charge transfer;

(d) colour from band theory: colour in metals, in semiconductors, in doped semiconductors and from colour centres;

(e) colour from geometrical and physical optics: colour from disper­sion, scattering, interference and diffraction.

This book is focused on the industrially important organic dyes and pigments and, to a certain extent, inorganic pigments and thus deals almost exclusively with colour generated by the mechanisms described by group (c).