At what illuminant temperature are Munsell neutrals (N6, N7, etc.) designed to be neutral?
The Munsell samples are specifically designed to be viewed under CIE illuminant C (simulated daylight with a correlated color temperature of about 6774K). However the actually samples are quite spectrally nonselective (i.e., flat spectral reflectance curves) and should appear neutral under a variety of white light sources.