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Lightbulb temperatures

  1. May 23, 2005 #1

    Pengwuino

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    So i was checking out some lightbulbs a while back and i noticed they had these numbers on it. One type had the number... it was like 3100K and the other was 5500K or so. Are these the temperatures corrposponding to the blackbody radiation associated with those temperatures? I know theres 2 types of lightbulbs generally... the whiteish type (or well, i mean the color of light given off) you see in offices and the yellowish you see at home. Now the thing is... the whiteish type... i thought white light was just the combining of light? How could it have a temperature associated with it? Any help on all this would be .. helpful :D Plus does anyone know which, the 3100K ish or the 5500K ish will produce the normal home-type yellow light?
     
    Last edited: May 23, 2005
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  3. May 23, 2005 #2

    FredGarvin

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  4. May 23, 2005 #3

    Pengwuino

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    sweet thanks
     
  5. May 23, 2005 #4

    brewnog

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    The temperatures you have seen refer to the colour temperatures of the light given off.

    These values are of particular interest to photographers, who will need to know what sort of film to use such that their pictures look like the original scene did.

    The higher the colour temperatures (measured in Kelvin, but nothing to do with the actual bulb temperature), the bluer the light it gives off.

    Normal incandescent bulbs operate at around 2900K, which as we know is a kind of yellowish colour. 'Warm white' fluorescent tubes are around 3500K, which are a pale yellowy white. "Cool white" is around 4100K, which is an almost greeny yellow. 'Daylight' bulbs range from 5500K to 6500K; the upper end being bluish. Sunlight is said to be around 5000K, and daylight up to 7500K.

    Anyway, that's my knowledge from my photography days, perhaps someone can put some more science into this.


    Edit: Dammit, Fred beat me to it...
     
  6. May 24, 2005 #5

    Danger

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    But does the colour temperature have anything to do with how far it will make a coin jump? :tongue:
     
  7. May 24, 2005 #6

    brewnog

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    Oh, I forgot all about that! We'll have to work on that more when I've finished exams...
     
  8. May 24, 2005 #7

    Danger

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    Good! I've thought about reviving that thread a couple of times, just to make sure that someone eventually tells me what's going on.
     
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