[chessplayer]

white is a color.

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White is a combination of all colors. Black is actually absence of color.

[RegulatorCountry]

Speaking of luminance that's true, as with an LCD or color monitor. White is full spectrum, the totality of color. Black is it's absence.

Speaking of reflectance it's the opposite. Black is the totality of color and white is the absence of it, as with printed matter, really anything in nature that is not a light source in it's own right.