Editing Fluorescent lamp (section)

===Color rendering index===
[[File:Helical fluorescent lamp spectrum by diffraction grating.JPG|thumb|A helical cool-white fluorescent lamp reflected in a [[diffraction grating]] reveals the various [[spectral lines]] which make up the light.]]
[[File:Various lighting spectrums - Flurescent incandescent diode and candle.jpg|thumb|Fluorescent spectra in comparison with other forms of lighting. Clockwise from upper left: Fluorescent lamp, [[incandescent bulb]], [[candle]] flame and [[LED lighting]].]]
{{Main|Color rendering index}}
Color rendering index (CRI) is an attempt to measure the ability of a light source to reveal the colors of various objects faithfully in comparison to a black body radiator. Colors can be perceived using light from a source, relative to light from a reference source such as daylight or a blackbody of the same [[color temperature]]. By definition, an incandescent lamp has a CRI of 100. Real-life fluorescent tubes achieve CRIs of anywhere from 50 to 98. Fluorescent lamps with low CRI have phosphors that emit too little red light. Skin appears less pink, and hence "unhealthy" compared with incandescent lighting. Colored objects appear muted. For example, a low CRI 6800 K halophosphate tube (an extreme example) will make reds appear dull red or even brown. Since the eye is relatively less efficient at detecting red light, an improvement in color rendering index, with increased energy in the red part of the spectrum, may reduce the overall luminous efficacy.{{r|GE1978|p=8}}

Lighting arrangements use fluorescent tubes in an assortment of tints of white. Mixing tube types within fittings can improve the color reproduction of lower quality tubes.