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Thread: CRI for incandescent vs. LED bulbs

  1. #1
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    CRI for incandescent vs. LED bulbs

    I'm a bit confused about the Color Rendering Index for incandescent bulbs vs. LED ones. Incandescent bulbs claim to have a CRI of 100 (the highest possible), whereas a 5000K (daylilght) LED bulb claims to have a CRI in the upper 80's. However, under 5000K LED light in my bedroom or closet, I can see the colors of my clothing perfectly. Under incandescent lighting, I have trouble telling navy from black (pants, socks, etc). Before I installed 5000K LED's, I have mistaken black for navy several times.

    I might be one of the unusual ones, but I much prefer 5000K over 2700K. I know a lot of people, especially women, who cannot stand 5000K; they MUST have 2700K.

  2. #2
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    Quote Originally Posted by jeff48356 View Post
    I'm a bit confused about the Color Rendering Index for incandescent bulbs vs. LED ones. Incandescent bulbs claim to have a CRI of 100 (the highest possible), whereas a 5000K (daylilght) LED bulb claims to have a CRI in the upper 80's. However, under 5000K LED light in my bedroom or closet, I can see the colors of my clothing perfectly. Under incandescent lighting, I have trouble telling navy from black (pants, socks, etc). Before I installed 5000K LED's, I have mistaken black for navy several times.

    I might be one of the unusual ones, but I much prefer 5000K over 2700K. I know a lot of people, especially women, who cannot stand 5000K; they MUST have 2700K.
    it's a lot warmer white, and more forgiving on facial characteristic.
    5k is pretty stark.

    the higher kelvin led's seem to have more watts per lumen, from
    what i've seen. helps with the energy calculations per square foot
    in places like Calif. where such calculations make electrical engineers
    cry.
    ~New signature under construction.~
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  3. #3
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    Quote Originally Posted by Fulthrotl View Post
    it's a lot warmer white, and more forgiving on facial characteristic.
    5k is pretty stark.

    the higher kelvin led's seem to have more watts per lumen, from
    what i've seen. helps with the energy calculations per square foot
    in places like Calif. where such calculations make electrical engineers
    cry.
    At my age, I'm accustomed to restaurants asking me to pay in advance, but now my bank has started sending me their calendar one month at a time.

  4. #4
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    Quote Originally Posted by Fulthrotl View Post
    it's a lot warmer white, and more forgiving on facial characteristic.
    5k is pretty stark.

    the higher kelvin led's seem to have more watts per lumen, from
    what i've seen. helps with the energy calculations per square foot
    in places like Calif. where such calculations make electrical engineers
    cry.
    I think you mean more lumens per watt.
    The more they overthink the plumbing, the easier it is to stop up the drain

  5. #5
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    CRI - New Measurement

    The older CRI was measured against a few different "pastel" colors and actually used the incandescent lamp as the base source and compared other sources of light to it. There is a new source of CRI emerging that tests light sources against 99 different colors (not just the old 8 pastel colors that incandescent was measured against). This new CRI method provides a more accurate rendering index for colors of objects under those sources of light. We are seeing this more in hospitality/commercial sales and the likes where certain colors are desired to "pop" more. Source: http://www.laserfocusworld.com/artic...t-sources.html

  6. #6
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    Quote Originally Posted by dkidd View Post
    I think you mean more lumens per watt.
    I meant what he knew.

    Cheers and Stay Safe,

    Marky the Sparky

  7. #7
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    Quote Originally Posted by jeff48356 View Post
    I might be one of the unusual ones, but I much prefer 5000K over 2700K. I know a lot of people, especially women, who cannot stand 5000K; they MUST have 2700K.
    I wonder if people really prefer a 2700k or if it is just some sort of conditioning. Perhaps the whiter light makes people think of offices/industrial spaces and/or older flickery fluorescents? Or maybe the historically higher color temperature had lower CRI so people associate the whiter light with bad light? You would think people would prefer light closer to natural sunlight which would be on the other end of the spectrum from 2700K. Maybe its just coincidence, but lately I have seen more people buying higher color temperature.
    Ethan Brush - East West Electric. NY, WA. MA

    "You can't generalize"

  8. #8
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    The major consideration, I think, is that for indoor lighting people are more used to the lower color temperature of incandescents.
    I would not be surprised, though, if the cool white and daylight fluorescents have a lower CRI.

    FYI, the color rendering problem is twice as bad or more when dealing with film and digital imaging devices since they have unique frequency response spectra that are narrower than and different from those of the eye.

    Sent from my XT1585 using Tapatalk

  9. #9
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    Quote Originally Posted by GoldDigger View Post
    for indoor lighting people are more used to the lower color temperature of incandescents
    So I wonder if they actually like it better, or just think they like it better
    Ethan Brush - East West Electric. NY, WA. MA

    "You can't generalize"

  10. #10
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    Quote Originally Posted by GoldDigger View Post
    I would not be surprised, though, if the cool white and daylight fluorescents have a lower CRI.
    They generally do, but not because they're "cool white"/etc but because they're cheap junk. You can get flourescents that have a spectra even enough for TV lighting, but they are Not Cheap at all (try $20 for a 4' tube); studios have been using them for years, it's all a matter of getting the right phosphors.

    Quote Originally Posted by GoldDigger View Post
    FYI, the color rendering problem is twice as bad or more when dealing with film and digital imaging devices since they have unique frequency response spectra that are narrower than and different from those of the eye.
    Digital image sensors tend to have a wider valid spectra than the eye (they can pick up IR and UV that we can not, but they can lack in subtlety). Issue is that the human eye will merrily color-correct and fill in some of the missing colors while film or sensors won't. (One of the most painful things for a video engineer is to keep the grass the same color through an entire day-time baseball game or golf tournament.)

    There's also the problem of the mercury lines, which are very narrow but quite strong.

    I found a paper online that shows the spectral graphs of a bunch of lamps; you can see how the CRI relates to the evenness of the output.
    http://assets.sylvania.com/assets/do...5f6cac74b9.pdf

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