Could anyone help with provision of some data? I’m in need of reflectance spectra for coloured patches with known CIE xy. Essentially, reflectance spectra for the patches of a color checker target, though I don’t care what brand as long as the spectra correspond to known CIE xy chromaticities. I gather many years ago there may have been some data available on Bruce Lindbloom’s site, but it seems to be long gone and I can’t find it even on the archive.org version of the site. If anyone has such data available, or could measure it, that would be enormously helpful.
The purpose of this is to extend a feature I’m working on for Siril: spectrophotometric color calibration. This is an advanced color calibration system that uses stellar spectra from catalogues and models the expected flux given known sensor QE and filter transmittance. All that is done and soon to be merged: the next step is to assign the correct source profile. For dSLRs this can be done by copying the chromaticities from Darktable, however many of the imaging setups I am dealing with are mono sensors and filters that have not been calibrated as part of any photographic software. I do have the advantage, though, of knowing the QE curve and sensor transmittance, and also having a large library of white reference spectra. So I plan to compare (the computed RGB responses of a sensor + filters combination to a set of reflectance spectra) with (the actual xy coordinates corresponding to each reflectance spectrum in the set) and thus work back to a set of chromaticities to form the primaries of a source profile for the setup.