CRI for incandescent vs. LED bulbs

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jeff48356

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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.
 
jeff48356 said:
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.
Click to expand...

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.
 
Fulthrotl said:
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.
Click to expand...
:D
 
Fulthrotl said:
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.
Click to expand...

I think you mean more lumens per watt.
 
CRI - New Measurement

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/arti...ering-index-guidelines-for-light-sources.html
 
jeff48356 said:
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.
Click to expand...

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.
 
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
 
GoldDigger said:
I would not be surprised, though, if the cool white and daylight fluorescents have a lower CRI.
Click to expand...

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.

GoldDigger said:
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.
Click to expand...

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/documents/faq0041-0800.83f1d8de-3fe1-4d24-a209-d95f6cac74b9.pdf
 
GoldDigger said:
When FM radio was first introduced people disliked the "unnatural" sound of high fidelity audio compared to the familiar AM radio sound.
:)

Sent from my XT1585 using Tapatalk
Click to expand...

I Get weirded out watching a movie on newer TV's. This is an effect a certain percentage of the population gets. Not sure if its the high resolution or frame rate, but it looks like a soap opera or 80's BBC TV and I cant help but think "low budget"
 
jeff48356 said:
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.
Click to expand...

The fact that an incandescent has a CRI of 100 does not mean it is better at rendering color; it just happens to be THE standard that we compare other sources to. It scores better on the test because it is the test. Also, a source with more blues in it (ie a 5,000K LED) will be better at rendering the blues in your socks. Further, you may be getting more lumens from the LED than you are from the incandescent. Therefore it was easier to see the socks.
 
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