There were some press releases around that some ‘ultra-white’ paint with bariumsulfate was developed by a university, but this paint is not commercially available…
So I will stick to the titanium dioxide based paint, which was at least one of the best one I could get.

Yes, I noted this already… I already asked a friend that he will create a script with real-time graphic output and fully automatic file output to keep the time needed as low as possible.

Thank you for the explanation. So I will basically measure the incandescent one time outside the sphere (point the spectrometer directly to the light source) and then inside the sphere to compare the reflectivity of the paint at different wavelengths?

1 Thank