# (Color Temperature) How to calculate combined color temperature (kelvin) of two different sources

I have been looking for a while but I can't seem to find any information on this.

I would like to figure out the formula to calculate the CCT of two calibrated sources of light relative to their intensities, both for linear dimming curves and exponential dimming curves.

Suppose I have identical led emitters doped with 3000K and 6000K phosphors, how can I calculate a specified target color temperature? Is it a linear relationship between relative intensities? Suppose 20% and 20% intensity yields 4000K, will 60% and 60% also yield 4000K?

Thanks

• You'll need the exact power spectrum, i.e. watts at each wavelength. Then you can add them and recalculate the color from the luminosity function (see wikipedia). – PhysicsDave Apr 12 '19 at 0:41