 The ProPhoto RGB color space encompasses over 90% of possible surface colors in the CIE L*a*b* color space, and 100% of likely occurring real-world surface colors documented by Pointer in 1980, making ProPhoto even larger than the Wide-gamut RGB color space.The ProPhoto RGB primaries were also chosen in order to minimize hue rotations associated with non-linear tone scale operations.One of the downsides to this color space is that approximately 13% of the representable colors are imaginary colors that do not exist and are not visible colors.