• Alphabetic suffix that follows lamp part number, e.g., F15T8/CW, designates color temperature of lamp. The correlated temperature of a light source is expressed in Kelvins (K) and is a means of describing the appearance or chromaticity of the source itself. It describes the apparent whiteness of the lamp. Incandescent lamps deliver a limited color temperature range between 2700K and 3000K the same color range as a warm white fluorescent lamp.
  • Fluorescent lamps offer a wide choice of color temperatures from cool white (CW) 4100K that produces a bluish white light reminiscent of moonlight on cold snow; Warm White (WW) 2700K to 3400K light with a yellowish tint, reminiscent of fireplaces and candlelight to Daylight (D) 6000-6500K that is typical of mid-morning daylight entering through a window on a sunny day.
  • LEDs have three colors, bright white, cool white and warm white that are 3000K to 5000K.  The RED LEDs are 4000K only.