E21A Color Test with surprising result

I always thought Maukka’s CCT numbers were a bit low compared to reality. For example his test of the 219B SW45K leds showed them to be around 4200k, but they look more like 4700k.

Nice package, very efficient and trendy

Actually, from the diagram negative duv at such a high CCT is more blue that magenta as seen in in the CIE diagram. This perfectly explains the observation I posted here back in July about these E21s making plants look blue, not green at all.

Quote from July:

Suddenly everything is making more sense now that I have the data to back up my observations.

Your test of what I assume is a bare LED vs his test of integrated light is not comparable. You should throw a XML sized frosted or beaded TIR optic on top and see what you get

Yea I agree contactcr, that’s why last night I ordered some D-C-Fix to try and mitigate the issue. I don’t have a TIR optic to test with.

DC fix wont bring the light from the sides of the LED to the front like a TIR or reflector would though. A reflector with DC fix might be a good test

Well I can’t have a lens or reflector for normal use, I need a even light on the whole wall.

DC fix will probably work well enough for that if you are measuring a few feet away at least

Yea and if I get the D-C-Fix as close as possible to the emitter I should be capturing that side light, as well as scattering the center light.

A solid plan I think, like a photography light

This is weird. I’ve tested many E21A (photo comparisons etc…) and have been using them until today, none deviates that much from those in the data sheet. And many people also satisfied with them. To my eyes, 5000K and 5700K are two CCTs most resemble daylight. Only 6500K appears “too blue”. I said this not because I sell these LEDs, but E21A is very popular for reasons.
In my opinion, your profile picture looks way too cool if they’re 5000K E21A. Too warm WB perhaps? You can check my beam and tint shots for comparison.

[Clemence]

I’ve used probably 7-8 different reels of sw45k and they’ve measured anywhere from 4200K-4700K in a reflector, so I wouldn’t read into that too much. Plus bare LEDs, integrated LEDs, optics, and reflectors will all produce different results.

I trust what you are saying Clemence. But something is definitely up. Could there have been a mixup with some higher CCT ones in the same drawer when they were built, or just a different bin/batch?
BTW, both my quads perform same.

As for the profile pic, I believe the camera was set to 5000K as it should have been, but I can’t be sure anymore.

My sm653 Wizard has a much higher CCT with the bare LEDs measured head on than it does with an optic.

Turbo 2
CCT = 8792K (Duv –0.0082)
Color Rendering Index (Ra) = 93.4 [ R9 = 78.4 ]

Main 3
CCT = 7950K (Duv –0.0031)
Color Rendering Index (Ra) = 95.8 [ R9 = 87.2 ]

With the optic, the hotspot is 7301K and 6819K on the same levels, respectively. Sounds like your LEDs are behaving normally.

Forgot Joshk tested the LED at max 2A. That’s beyond the 1400mA limit for E21A. So, that’s normal. Maukka tested the LED according to Nichia’s binning current at 700mA.

[Clemence]

I got the Fluke out and perfected the Amps at 700 and ran the test again. Then graphed it all together.
—0 Degree 700ma—
CCT: 5949
Duv: –0.0058

—45 Degree 700ma—
CCT: 5390
Duv: –0.0017

When you put that in an optic or reflector or integrate the measurement it will probably end up being about 5000K.

I sure hope so. I’m learning as I go. Thanks to everyone for the help.
To be continued…

Would like to see the 90 degree measurement. In order to average to 5000k somewhere else in the beam would have to be less than 5000k.

The CCT measurement near 90 deg is 4700K, but it’s not all that bright out there.