scope:

This document describes a protocol for measuring photometric, colorimetric, and electrical characteristics of tunable-white solid-state lighting products- including lamps, luminaires, and light engines-as covered by ANSI/IES LM-79-19 (see Section 2.7). This protocol applies to products for which the spectral power distribution can be adjusted with a single, one-dimensional input having a quantitative, interval format, either continuous or discrete, that is nominally independent of luminous flux control. For example, a product controlled with one variable control input (e.g., slider, rotary knob)-or several presets-for color and one variable control input for lumen output. This document also describes a method for interpolating between measured data to obtain specified characteristics, including correlated color temperature (CCT) range, D_uv range, lumen output range (at full intensity control as color changes), efficacy at maximum output, efficacy range, color rendition range (i.e., IES R_f, IES R_g, IES R_cs,_h1, IES R_f,h1 CIE R_a, CIE R₉,), and chromaticity coordinates (i.e., x, y; u', v').

The method described in this document does not apply to products that intentionally change chromaticity with luminous flux (e.g., dim-to-warm), or products with multiple color-control input signals (e.g., full-color-tunable) that cannot be set to operate with a single color-control input signal. Some tunable-white products may use control schemes that are not covered by this method, such as a number of categorical presets that are not linked to an underlying scale or a graphical interface that does not provide a quantitative component.