I’m attempting to create estimated colourimetry calibration data for DMX controlled LED lights for the software MagicQ. (Chapter 27. Head Editor)
To create this calibration data, for each emitter in the fixture I need the CIE 1931 XY values, and the luminosity (which I can measure separately). A fixture can have some combination of LED emitters including red, green, blue, white, amber, UV, lime, or deep red.
My idea is to turn on each emitter in turn, shine it at a white surface, take a photo with my Nikon D750, and then use darktable to sample what each CIE 1931 XY value is. (I imagine this isn’t going to work well for certain emitters like UV and deep red, so I’d have to consider if the results are accurate.) I’ve taken some sample photos. I’ve used darktable in the past for photo raw photo processing, and I know that it supports CIE 1931, however I’m not finding the tools to sample these values this directly in darktable.
Before a waste a bunch of time or dive into libraw, does anyone have any suggestions for how I can get these CIE 1931 XY values from an image? (or any other comments on my approach)