Noble gas as in other metallurgical processes and in the production of silicon for the semiconductor industry. Noble gases are commonly used in lighting because of their lack of chemical reactivity. Argon, mixed with nitrogen, is used as a filler gas for incandescent light bulbs. Krypton is used in high-performance light bulbs, which have higher color temperatures and greater efficiency, because it reduces the rate of evaporation of the filament more than argon; halogen lamps, in particular, use krypton mixed with small amounts of compounds of iodine or bromine. The noble gases glow in distinctive colors when used inside gas-discharge lamps, such
Phase-out of incandescent light bulbs source is similar in character to that from a Planckian "black body" in spectral distribution, that is, the bulb, as the filament heats up, produces light from wavelengths throughout the visible spectrum. Alternative light sources use phosphors or combinations of mono-chromatic LEDs (red, blue, green) to produce "white" light, giving significantly irregular spectral distributions which can result in color casts in photography and differences of color matching when compared to incandescent light or daylight. Halogen lamps are a type of incandescent lamp with improved efficiency over regular incandescent lamps. Though not as energy efficient as other alternatives, they are up