In accordance with the ISO 13655 standard, the “M” series of measuring mode settings were defined in order to standardize illumination conditions where optical brightening agents are utilized in substrates. The following is designed as a quick reference chart of the 4 different measuring mode settings within the “M” series.
M0 “Color measuring mode A” spectral luminance factor without polarization filter under a light source that simulates standard illuminant A (gas lamps or LEDs, 2856 ± 100 K, from 420 to at least 700 nm)
M1 “Color measuring mode D50” spectral luminance factor without polarization filter under a light source that simulates standard illuminant D50 with correct UV component < 400 nm (theoretically F8 fluorescent lamp, in practice only LEDs incl. UV LEDs, 5003 ± 100 K, under 380 to at least 700 nm)
M2 “Color measuring mode UV Cut” spectral luminance factor without polarization filter under a light source that simulates any standard illuminant without UV component (gas lamps with UV cut-off filter < 400 nm or LEDs without UV LED, from 420 to at least 700 nm)
M3 “Measurement with polarization filter” spectral absorption degree (with RGB filters) or spectral luminance factor (with spectral scanning head) with polar ization filter pair (in radiated and in reflected light, crossing each other) under a light source that simulates any standard illuminant (gas lamp or LEDs, from 420 to at least 700 nm).
M2 (UV Cut), through the comparison with a mode with UV component (M0/A or M1/D50 – depending on the selected illuminant in M2), allows the measurement of the effect of optical brighteners for suitably high-quality ICC profiles. M3 is suitable not only for measuring color density (absorption under polarization filter) but also for color measurement of wide gamut inks, effect pigment inks and for printing ink recipes (remission under polarization filter). Techkon spectrodensitometers automatically move the polarization filter in or out when the mode is changed. In this field of application, Techkon evaluates the effect of optical brighteners through empirical algorithms.
Definitions provided by:
Expert Knowledge in Color Communication | Color in Media Design, Prepress and Print
published by Johannes Kokot and Dieter Kleeberg
in cooperation with the color communication project group.