M0 Measurement

/ˈɛm ˈzɪərəʊ ˌmɛʒəˈmənt/

General Definition

M0 Measurement is one of the measurement conditions (M Factor) defined in the international ISO 13655 standard for color specification. In this mode, measurement is taken by a spectrophotometer under D50 reference illumination without applying any ultraviolet (UV-Cut) filter. Consequently, the device's full spectral response, including all UV energy from the light source, is recorded. This method was theoretically designed to assess the behavior of materials containing optical brightening agents (OBAs) and fluorescence when exposed to UV-containing light.

Real-World Usage

Although M0 was intended to measure the full effect of OBAs and fluorescence, it faces fundamental practical challenges. The primary issue is the lack of repeatability. Since the exact amount and distribution of UV in the D50 light sources vary across different manufacturers' instruments, measuring the same sample on two different devices can yield different numerical values, violating a core principle of measurement science.

Furthermore, M0 exaggerates the effect of OBAs and fluorescence unrealistically because real-world viewing environments are never exposed to the same amount of UV as a laboratory light source. This leads to a discrepancy between the measured color and the perceived color. In contrast, M2 Measurement, which completely excludes UV, is suitable for non-fluorescent materials but ignores the effects of OBAs and fluorescence.

Consultant's Note

Due to M0's inherent problems, the modern printing industry standard has rejected its use for any practical measurement, calibration, or profile building. Today, the M1 Measurement condition is the mandatory, precise, and repeatable replacement for M0 in specifications like FOGRA and GRACoL. M1 uses advanced technologies (such as controlled-spectrum LEDs) to simulate the effects of OBAs and fluorescence in a standardized and comparable way across all devices.

A strong advisory recommendation is to define your measurement protocol based on M1. When sourcing or receiving color data, always be aware of the measurement condition (M0, M1, M2, M3) used. Adhering to M1 makes your supply chain, from design to print, predictable and robust.

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