electromagnetic spectrum

electromagnetic spectrum (In French spectre électromagnétique) wavelengths emitted by electromagnetic radiators; ranges: low frequency radiation 100000 to 100 km, high frequency radiation 100 km to 1 mm, optical radiation 1 mm to 200 nanometers (1 nm = 1 millionth of a mm), ionizing radiation 200 nm to 0.1 femtometer (millionth of a nanometer). Optical radiation, which is responsible for the formation of color stimulus and which is relevant for print and media, is subdivided as follows: – ultrared (“infrared”, IR, heat radiation) 1 mm to 780 nm (including laser for thermo-CtP printing plates, dispersion varnish drying, photoconductor illustration in laser printer systems); – visible radiation (“VIS”, light spectrum, spectral colors redorange- yellow-green-blue-violet, mixed colors) 780 to 380 nm (all light sources, color-matching booths, standard illuminant lamps, light-emitting diodes, gas/solid/diode color lasers for CtP printing plate illustration, LED UV printing ink drying, monitors, data projectors, measuring light in colorimetric measuring instruments, remission area of optical brighteners in fluorescent printing inks and papers); – near ultraviolet (UV-1, UV-A/B/C, “quartz UV”, “black light”) 380 to 200 nm (absorption range of optical brighteners, mercury/metal halide lamps for hardening UV inks/paints and hybrid printing inks as well as the illustration of photopolymer flexo printing plates, exposure of diazo copying layers). Despite their invisibility, UV and IR rays are regarded as optical radiation, because they can be refracted/reflected and acousto-optically modulated within certain limits, like light, using optical systems (lenses, grids, mirrors).