[5.9.9]

Fluctuation in luminous quantity or spectral distribution of light with respect to time. (Source: CIE TN 012:2021.) 

Note 1: TLM may also be thought of as a light stimulus with a waveform that exhibits time-based modulation, sometimes called “flicker,” though this an imprecise term and therefore not recommended.

Note 2: The pattern of luminous quantity typically fluctuates in a cyclical way but is potentially aperiodic or asynchronous. 

Note 3: The TLM waveform can vary widely and may or may not produce a visual or nonvisual response; it is merely the documentation of the luminous quantity variation. A steady (e.g., from direct current, DC) light output is also a form of TLM exhibiting no modulation or modulation that cannot be detected within measurement limits.

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