Abstract: Special commercially available fluorescent lamps of warm-white correlated color temperature of about 3000.degree. K. have both good coloring index and efficacy. These lamps utilize as the light-emitting component a special three-component phosphor blend having emissions principally confined to the wavelength regions of from 430 nm to 485 nm, from 515 nm to 570 nm, and from 588 nm to 630 nm. This phosphor blend is relatively expensive and to decrease expense, it is known to utilize an undercoat of halophosphate phosphor of the same emission color, which decreases the amount of expensive phosphor required.

Abstract: Fluorescent lamp has warm-white color and both high efficacy and good color rendition. This performance is achieved by utilizing a broad-band-emitting apatite-structured calcium fluorophosphate activated by predetermined percentages of antimony and manganese and narrow red-orange-emitting yttrium oxide activated by a predetermined percentage of tervalent europium.

Abstract: To improve the performance of fluorescent lamps which use strontium chloroapatite activated by a divalent europium as a luminescent material, prior to coating onto the lamp envelope, the luminescent material is washed with an aqueous fluoride solution and then rinsed to remove residual soluble fluoride.