What does higher CRI really means?

I've always thought higher CRI of Incans (CRI>90) tells the true color better than most LEDs (CRI 70).

But some recent beam shots got me kind confused.

Outdoor Beam shots:
The Incan on left, Mag 1185 tells me the tree is yellow.

The LEDs Aspheric Mag (Middle) & WF500 5xCree (Right)
both only 70 CRI & both tell me the tree is Green.

So, the Incan with higher CRI is telling me the wrong color?


Why is high CRI leds so popular these days (They are usually ~4000 kelvin & yerllow looking) so popular if it's not going to tell the true color of things?

beamshots do not always tell the true color of things due to different camera white balance settings, incans will appear yellow if the wb is set to daylight and LEDS and HIDS will be blue if the wb is set to tungsten

CRI and tint are two different things, you can have a light that has a significant tint that is still 100 CRI. A good example is candlelight vs parking lot metal halide; both are shifted significantly into the warm/orange, yet the candle's 100 CRI still gives you the ability to differentiate all colors, while the HID's 25 CRI makes everything look monotone and washed out.

See page 13
http://www.philipslumileds.com/pdfs/DS63.pdf
compare the two 4000K offerings.

I'd love to retrofit of my Fenix p2d rebel with the LXM3-PW51

Tint seems exaggerated when compared side by side, and your camera's automatic white balance is also playing a role.

It looks like a good example of high CRI to me, though.

You can see the bush's branches (brown) with the incan. You cannot see them with the cool tinted LEDs. Much of the light a cool white LED puts out is green, so the leaves should appear to pop while nothing brown or red does.

StarHalo said:

CRI and tint are two different things, you can have a light that has a significant tint that is still 100 CRI. A good example is candlelight vs parking lot metal halide; both are shifted significantly into the warm/orange, yet the candle's 100 CRI still gives you the ability to differentiate all colors, while the HID's 25 CRI makes everything look monotone and washed out.

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The parking lot lights you are talking about would be High Pressure Sodium, They produce a nasty orange light. Metal Halide produce a whiter light, but shift color throughout the life of the bulb. Not that this matters to the thread so much, but I hate HPS:sick2:

-Bobby

nakahoshi said:

The parking lot lights you are talking about would be High Pressure Sodium, They produce a nasty orange light.

Click to expand...

Ah, that's the one, thank you.

The low-CRI effect of these is really amazing though, you can literally open a box of Crayons under one and you can't tell which color is which..

CRI is a measure of how close the spectrum a light source is to the spectrum of a blackbody radiator of the same apparent color temperature. A Blackbody radiator would be a source such as a candle, incandescent filament, or the sun -- so incandescents are defined as CRI 100. Same is sunlight. However the two are NOT equal in how they render color compared to each other.

Where CRI would be relevant would be comparing light sources of the same color temperature. For example, you could compare your LED to a fluorescent lamp, or to daylight of similar color temperature, and that might give you some useful information. Your LED (70CRI) will probably be somewhat worse than a decent daylight fluorescent (say 85-90CRI), which will be not quite the same as real daylight (defined as 100 CRI).

In general though the term is confusing as the difference in color tempreatures can be as significant, if not moreso, as the difference in CRI between two sources at the same color temperature.