Green Blue Luxeon

I tested out a Cyan 1W Luxeon, and it's GREEN!

I thought that I would email the supplier and tell them they sent me the wrong one, so I took a photo to attach as some evidence, and hey presto, the LED turns out a very nice Cyan. Wha...?

I tried fiddling with the white balance on the camera, tried with and without flash, tried putting reference objects in the photo (ie to see if they change colour too). No good. No matter what I do, the Lux turns out Cyan, and everything else in the shot looks just like it should.

I tried this with a Canon Powershot A80, and also a Canon EOS 10D. Both do the circuis trick. I showed it all to a graphic designer friend, and she confirmed green before, cyan after. So it's not just my dumb male colour blindness.

Does anyone have any explanation. I assume it's the CMOS in the cameras, but the two (although the same brand) use different types.

Curious.

Actually, dont't send your camera for repairs yet because I think it's just the way it is. I got a cyan EL blaster 6 for my bro some time ago and it looked green to my eyes but when I opened it for him later, the bin code does refer to a cyan luxeon.
Maybe it has something to do with the fact our eyes are very sensitive to the large amount of green light emitted...

Most blue-green (cyan) LEDs, both Luxeon and 5mm, are a bit more greenish than they are bluish. LED manufacturers make them this way on purpose, rather than accidentally.
What you probably have is what's known as "traffic signal green", and emits with a peak wavelength between 507nm and 515nm.

Several years ago, a color called "Tokyo blue" was much more common, and had a peak wavelength of 490nm to 500nm.
The most common use for cyan LEDs, the green lights in traffic signals, dictated the change. Tokyo blue was too bluish, so LED designers started making greener-tinted cyan LEDs to cater to traffic signal makers. These made the green lights in the traffic signals look green, but they still emit enough blue to be visible and distinguishable to somebody with red/green colorblindness.

The "Positron Laser" that I received in late 2002 has a 5W cyan Luxeon emitter generating radiation peaking around 495nm, and it really is cyan.

I did see the post about Green luxeons through a red filter, which showed that a lot more light of surrounding wavelengths gets through than it appears from Lumileds' charts. I suppose that it must be due to the green light that is emitted, and the eye's higher sensitivity to that light, as you say, kongfuchicken.

It must work with the traffic lights. I have quite a few colour blind friends who can tell if they are green or red, thank goodness! I never thought to ask them the colour of the LED though ...
Must try it.

It really does intrigue me that the camera interperets it so much differently compared to the eye.

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The_LED_Museum said:
Several years ago, a color called "Tokyo blue" was much more common...
...Tokyo blue was too bluish

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In Japan, blue is commonly used for the same function as green in stoplights in the US.

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idleprocess said:
In Japan, blue is commonly used for the same function as green in stoplights in the US.

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That's how I understand it too.
Even Japanese anime cartoons like Digimon have light blue lights in traffic signals where you would see green ones in the US.

Green ones in Australia too.

Incidentally, all the new ones are LED, but the older ones are still incan, until they blow, then LEDs are put in there.