Yes, it has such a potential (what's the gamut of the scene, the film used etc?). And a color target who's gamut is sufficiently large enough a container to define an input profile to get to a large RGB Working Space gamut. The ProPhoto RGB color space, also known as ROMM RGB (Reference Output Medium Metric), is an output referred RGB color space developed by Kodak. It offers an especially large gamut designed for use with photographic output in mind. 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. ProPhoto RGB color space - Wikipedia Usually or never? You understand, there's no reason to guess and no harm using a container for a color space that is KNOWN to be large enough. Hence, ProPhoto RGB.