The frontend you see is RGB due to the internet and the display you're using. But on the backend (the manufacturer's system, no idea what the web site employs) the color science is all in spectral data. The xyz color matching functions [1] can be used to determine human response to that spectra, and then to 'CIE L* a* b*' for unambiguously referring to the color. The typical white in the paint industry is CIE illuminant D65.
You're right to wonder about "what is white" which gets into topics of 'chromatic adaptation', 'color constancy', and 'discounting the illuminant'.
If you get a perfectly diffuse white tile, what color is it when illuminant by incandescent versus fluorescent? And there are more than a few CIE F illuminants, and more proprietary ones. And hence each application tends to standardize on, and thus assume, an illuminant. You can use some other illuminant if you want, but then you're in custom territory and it wouldn't surprise me if some companies are doing that, secret sauce.
In special cases like automotive and textiles, it's common to see multiple spectral values due to different colors at different angles, and thus spectrogoniometry.
Comments
The frontend you see is RGB due to the internet and the display you're using. But on the backend (the manufacturer's system, no idea what the web site employs) the color science is all in spectral data. The xyz color matching functions [1] can be used to determine human response to that spectra, and then to 'CIE L* a* b*' for unambiguously referring to the color. The typical white in the paint industry is CIE illuminant D65.
You're right to wonder about "what is white" which gets into topics of 'chromatic adaptation', 'color constancy', and 'discounting the illuminant'.
If you get a perfectly diffuse white tile, what color is it when illuminant by incandescent versus fluorescent? And there are more than a few CIE F illuminants, and more proprietary ones. And hence each application tends to standardize on, and thus assume, an illuminant. You can use some other illuminant if you want, but then you're in custom territory and it wouldn't surprise me if some companies are doing that, secret sauce.
In special cases like automotive and textiles, it's common to see multiple spectral values due to different colors at different angles, and thus spectrogoniometry.
[1] https://en.wikipedia.org/wiki/CIE_1931_color_space