I know that by now it might be considered as a kind of sad recurrent joke, but by chance, does anyone here has the least information about the colorspace of RGB values in the MERL BRDF measurement database ?
Was interested in this myself and did some digging, I was wondering if they where spectral, but it appears not (although some interesting work on spectral BRDF is here http://web.cs.wpi.edu/~emmanuel/courses/cs563/write_ups/cliffl/cliffl_spectral_brdf.html )
This chat seems to indicate they are camera native linear, probably with sRGB primaries.
Someone points me that this article describes the spectral response of the camera the MERL paper used, and even provides colour transform matrices at the end. Unfortunately, using those transforms result in even worse results than assuming sRGB primaries.
Disney have a tool that analyses the database.
Is browsing the source code for this an option?
You could contact the authors perhaps?