The M0 condition has been declared obsolete due to two fundamental flaws. The first and most critical reason is the lack of repeatability in its results. Since the exact amount of ultraviolet (UV) radiation in the D50 light sources varies across different manufacturers' instruments, measuring a single sample on two different devices can yield different numerical values. This violates the core principle of reliability and comparability in scientific measurement.

The second reason is its unrealistic output. M0 exaggerates the effect of optical brightening agents (OBAs) and fluorescence in a way that does not correspond to the lighting conditions of real-world viewing environments. This leads to a significant discrepancy between the measured color and the color perceived by the human eye. Consequently, authoritative industry standards like FOGRA and GRACoL have discontinued its use for any practical work.