I provide measured spectra of 29 commercially available LEDs spanning the range from 380 to 660 nm peak wavelength.
The file contains one SPD per line. Each spectrum is given in 176 samples from 350 to 700 nm normalised to a unity power integral.
https://haraldbrendel.com/files/led_spd_350_700.csv
Below is a graph of the LED spectral power distribution.
The following figure shows the color of each LED in the xy diagram (begin of arrow) and the reproduction in the ALEXA camera system balanced to D65 (end of arrow). The solid line is AP0 and the dashed line is AP1.
This illustrates the rather complex situation. The color reproduction error of the camera system shifts some colors outside (examples are LEDs with peak wavelength between 400 and 458 nm). I think that is what many users of ACES with ALEXA footage have experienced. Other colors are shifted inside (LEDs with peak wavelength in the range from 480 to 500 and longer wavelengths around 640 nm). The color reproduction error “replaces” a gamut mapping from AP0 to AP1!
I would not put much confidence in the reproduction of the LED with peak wavelengths below 400 nm (enclosed by purple ellipse) because the UV blocking filter attenuates these wavelengths. Thus the chromaticities are the result of dividing small small numbers by small numbers.
I would like to emphasise that it’s not possible to clearly define regions in the chromaticity diagram where the color reproduction error of the camera is small or large. Compare the errors (length of arrows) for the LEDs with peak wavelengths of 472 and 480 nm with others in between. The result of the color reproduction is determined in the higher-dimensional spectral space of which we see a projection only.
