and y 0 408 that of the standard cool white fluorescent lamp is about x 0 367 y 0 384 that of the gold fluorescent lamp is about x 0 517 y 0 479 the chromaticity of a lamplight will not actually indicate its apparent color recall that an incandescent lamp inside a home but observed from outside in average daylight appears very yellow but after dark from inside the home the same lamp appears quite white two types of illumination may of course have the same chromaticity but be very different in their other characteristics for example average daylight 6500 u00b0 k and the standard daylight fluorescent lamp both have a chromaticity of about x 0 315 y 0 335 in the white region of the diagram their color rendering characteristics are however quite different 34 color temperature 34 is a convenient way of specifying the color of certain familiar and useful lights the white light from an overcast sky is one of these it is one of a unique series of natural lights characteristic of incandescent glowing bodies like the sun at one end of this series of lights is the glow from a red hot poker in a blacksmith 39 s shop 34 red hot 34 corresponds to a temperature of about 1000 u00b0 kelvins 1300 degrees fahrenheit the reddish color is characteristic of an incandescent body at 1000 u00b0 kelvins the incandescent tungsten filament in the household lightbulb near 2800 u00b0 kelvins glows with a yellowish light sunlight has the color of a glowing body at about 5000 u00b0 kelvins and blue.