CREEs XLamp ANSI white region plot is different in this updated chart. It's shifted!

ledmitter_nli · Sep 13, 2013

In the colored chart (from flashlightwiki and numerous other sources) the ANSI white curve line runs nearly through the middle of 5C1.

But on CREE's updated XLamps binning and labeling document (page 12) it now runs one region below to 5D2.

Isn't that a big wtf for anyone else?

uk_caver · Sep 13, 2013

I'll have to look back through old datasheets, but the jpgs of the graphs I use for quick reference look like your monochrome one, and I chopped them out of a CREE datasheet 3 years ago.

Update: - looking at an XR-E datasheet from 2007, the curve is in essentially the same place for bins 4-7, running just below the boundary line between 4A:4B through 5D:5C, along the boundary in the 6s, slightly above in the 7s.

uk_caver · Sep 13, 2013

The flashlightwiki one doesn't look like it's Cree's production:

Chromaticity chart with divisions used by Cree and Philips Lumiled with some subdivisions used only by Cree. This chart was generated by CPF user DFiorentino and is used at Flashlight Wiki by permission.

Maybe different maths used to generate the black body line?

uk_caver · Sep 13, 2013

Bear in mind we are only talking about something like 1/3 of a Cree sub-subdivision difference from a curve which is still somewhat arbitrary in subjective terms.

Sure, the black body curve has a physical definition, but especially in the warmer colours, thinking of it as 'white' might not be too useful.

Personally, I couldn't say I often notice a significant difference between LEDs from neighbouring subdivisions (like 2C and 2D), and this difference in line position is 1/6 of a subdivision.

Disciple · Oct 25, 2013

Interesting find. Has anyone done a side-by-side comparison of any of the equivalent CCT 5 bin tint pairs to see which looks better? I mean these pairs:

5B1:5A2

5B4:5A3

5C1:5D2

5C4:5D3

CREEs XLamp ANSI white region plot is different in this updated chart. It's shifted!

ledmitter_nli

Flashlight Enthusiast

uk_caver

Flashlight Enthusiast

uk_caver

Flashlight Enthusiast

uk_caver

Flashlight Enthusiast

Disciple

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