I searched the forum a bit and found this old post comparing some tools to detect cct, one of which is a smartphone app.
I looked for a few more android apps and found an interesting one, “White Balance Kelvin Meter”. I tried it with a 3000K ceiling light bulb and a Nichia 519a 5000K. As it is not a calibrated instrument, the values are quite different, as you can see from the screenshots below.
I then tried calibrating it but not being sure about my LEDs the whole thing is a bit useless. I then noticed an interesting thing, it gives indications on the DUV. I don’t know how accurate it is.
Would anyone have the will and patience to try it with some known lights and see if it is at least somewhat accurate or if it is nowhere near as accurate as an instrument like the Opple LM3?
The accuracy would depend a lot on the phone being used. I imagine there is a lot of variation in the accuracy of different camera sensors, not to mention different os versions and other hardware differences.
One could possibly try and calibrate against known light sources, but the given measurements would still be best used as a comparison between lights vs giving official numbers. It would be fun to experiment with for sure!
