Can we measure Kelvin values for flashlights with an App? Or other cheap way.

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ChibiM
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Can we measure Kelvin values for flashlights with an App? Or other cheap way.

Just searching for a way to measure (estimate) the color temperature of leds. 

I came across an Android App named: White Balance Colore Temp Meter, but it hasn't been updated since 2012 and am not sure that it will actually work well for flashights. 

So I basically have 2 questions: 

  1. Is there an App that can do this
  2. Is there another way to measure color temperature of a flashlight (LED)
Edited by: ChibiM on 01/16/2020 - 02:41
Yokiamy
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Apparently there are measurement devices for that, some which work with an app

Like these

Or this one

ChibiM
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So we can't really trust our light sensor of our phones? Would be nice to have an Android App, that uses the light sensor to measure color temperature. 

wle
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it probably is not accurate enough, or would require special calibration, or precise input data [like ‘exactly how bright is this light at this moment?’.

wle

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I tried with my LG G6 phone which has a manual camera mode. The white balance is given in ºK. Unfortunately it’s quite off. Tested against my best known light with an Arrow XHP50 5000ºK 95 CRI and matches at 3800 º. Tried with an XML-2 4400º K and again was way off ~ 3200º. So there would need calibration to work depending on camera sensor.

Sure would like to try with a newer Sam phone, supposed to be better optics and sensor.

ChibiM
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Interesting. In the link Yokiami posted is shown an analog meter as well. Those are probably affordable. Those digital ones look expensive.

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ChibiM wrote:

So we can’t really trust our light sensor of our phones? Would be nice to have an Android App, that uses the light sensor to measure color temperature. 


The light sensor on the phone is really analogous to a lux meter. It doesn’t detect color really.
The camera could be useful, if calibrated properly. Unfortunately, they’re not.

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ChibiM
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Pity!

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Thinking loud: One could take an older digital camera (RAW mode enabled), remove the Bayer Matrix, and take a shot of the beam after going through a prism (large distance between light and prism). Now you have the spectrum in terms of grey values, ready to be analysed by Image/J or other image processing software. Anyone tried this?

ChibiM
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I could probably do that, but that's quite a bit of extra work. I could aim the beam at a piece of white paper and use Lightroom to have the values... Hmmm. Wondering if that works.