M2 Measurement is considered obsolete because its UV-Excluded nature prevents the measured spectral data from accurately reflecting what a human observer sees under the standard D50 light (which contains UV).

For papers with OBAs, using M2 means the measured L*a*b* values are artificially skewed (less blue) compared to reality. This failure to incorporate the phenomenon of Fluorescence violates the principle of visual predictability in color management, making M2 an unreliable mode for controlling quality and communicating color specifications