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Thread: WHY the oxymoronic descriptions of light bulbs?

  1. #1

    WHY the oxymoronic descriptions of light bulbs?

    Why is it we drive on parkways, and park on driveways?

    And why is it that our sun is certainly yellow-ish, and 'cool' colors are blue-ish, but the light output of "cool-white" bulbs is yellow and "daylight" bulbs are blue...?
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  2. #2
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    I think it has more to do with color rendering than actual light color. Daylight bulbs generally give colors that are closer to what we see outside on a sunny day.
    Lee Schierer
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    if in reference to LED bulbs:

    https://en.wikipedia.org/wiki/Color_temperature

    because LEDs are doped with phosphors to produce a certain wavelengths of light, and the sun puts out the full spectrum of colors.

    also see the charts here: https://www.soundandvision.com/conte...ctrum-and-more


    more expensive bulbs are generally better. I stick with Cree.

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    Hi Kev, after your query on "light bulbs" I'm going to tease you about that, they're not "light bulbs", they're lamps

    As for the red being "warm", it's not in physics, light at the blue end of the spectrum is emitted with more energy by warmer objects than light in the red spectrum.

    I think it's because we see fires and red hot objects as warm physically, so we go with what we feel as humans...........Regards, Rod.

  5. #5
    Years ago, I had a friend at the same firm that had a peculiar sport coat. Under florescent light it appeared green under sunlight it appeared brown. My wife has trouble distinguishing between black and navy blue under most artificial light. Same for dark green and dark brown. A light bulb that cures this problem would save me from sometimes telling her that her socks don't match.

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    And why is it that our sun is certainly yellow-ish, and 'cool' colors are blue-ish, but the light output of "cool-white" bulbs is yellow and "daylight" bulbs are blue...?
    The color spectrum of artificial lamps is often designated in degrees Kelvin. The incandescent lamps of old were a nice amberish glow of about 2700 to 2800º K. Our brain adjusts our seeing so we would see this as making white paper look white.

    In the days of using film in photography there were some available for use in artificial light. Lamp color balance in film photography was a bit tricky at times.

    Here is a chart that explains it a little:

    Kelvin Chart.jpg

    Other charts may indicate the color metal glows at the various temps.

    jtk
    "A pessimist sees the difficulty in every opportunity; an optimist sees the opportunity in every difficulty."
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    "Good grief", I find the question "seriously funny" but that's just my "unbiased opinion."
    My three favorite things are the Oxford comma, irony and missed opportunities

    The problem with humanity is: we have paleolithic emotions; medieval institutions; and God-like technology. Edward O. Wilson

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    Even though the light from the sun is more toward the yellow spectrum, when it gets bounced around on our planet it tends to turn more bluish because of the nature of the shorter wavelengths. That's why things far away are blue as is our atmosphere (the sky).

  9. #9
    I just searched- everyone explained way 'daylight' is blue, but none of ya's explained why bulbs-- err, lamps- that produce bright yellow light are 'cool white'.

    And as to bulbs are lamps and lamps are fixtures-- check most lighting website, they refer to them as 'bulbs' more often than not, because-- WE do g
    ========================================
    ELEVEN - rotary cutter tool machines
    FOUR - CO2 lasers
    THREE- make that FOUR now - fiber lasers
    ONE - vinyl cutter
    CASmate, Corel, Gravostyle


  10. #10
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    Lamps do not create light, they suck in the dark, and are called Dark Suckers.
    Never, under any circumstances, consume a laxative and sleeping pill, on the same night

  11. #11
    There is no mistake that light bulbs produced very yellow light for a long time.

    It's the most efficient color for your eyes... You perceive that the room is much "brighter" for the same lumen output with the yellowy lamps...

    The blueish white lamps are opposite... They are more "brilliant" but are extremely inefficient for your eyes... They appear very "white" but it takes WAY WAY more actual lumens before your eyes can do anything useful with it..

  12. #12
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    Kev

    Light bulbs don't give off light, they absorb darkness. The speed at which they absorb darkness, determines the color. When they're full, they can't absorb anymore darkness, and that's why it's dark.
    It's true! Trust me.
    "The first thing you need to know, will likely be the last thing you learn." (Unknown)

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    Quote Originally Posted by Mike Cutler View Post
    It's true! Trust me.
    Oh no ! You're sounding like a politician.

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    Quote Originally Posted by Yonak Hawkins View Post
    Oh no ! You're sounding like a politician.
    or maybe a Glowforge Company rep.

  15. #15
    Quote Originally Posted by Perry Hilbert Jr View Post
    Years ago, I had a friend at the same firm that had a peculiar sport coat. Under florescent light it appeared green under sunlight it appeared brown. My wife has trouble distinguishing between black and navy blue under most artificial light. Same for dark green and dark brown. A light bulb that cures this problem would save me from sometimes telling her that her socks don't match.
    This is our world in wood lol. I joke with employees all the time to just go with thr color match and forget it. You can take a finished board, door, whatever, and move around the shop and watch it change color. Fourescents push green, leds (non color corrected) push white/blue, incandescent yellow, take it to a plate window another color, low e another, outside another, now you add in wall color and the color of reflected light (carpet color on a job can wreak havoc).

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