New methodology for measuring color performance


APRIL, 2018

Metodología de color



Índice de fidelidad cromática

Feeling Wood


The Lighting Engineering Society (IES) of the United States published a technical report that presents a new methodology to measure color performance, which would facilitate identifying the most appropriate light source for each application. It is the so-called TM-30-15.

This new methodology aims to replace the CRI as a standard measure for chromatic reproduction since it is limited when using this method for solid state technology lamps.

Limitations of the current IRC measurement system

The starting limitation is that the IRC is measured by a simple and single value within a numerical scale while light is a rich space in which tones, saturation and brightness are combined in different ways offering very different values. It is difficult for a simple measure to reveal everything about the color quality of a light source.

The color space used by the IRC is obsolete and is no longer used for standards except for IRC calculations and correlative color temperature determination (CCT). The color space whose nomenclature is W * U * V * is obsolete due to a noticeable distortion, especially in the red region. The set of colors used as a reference to calculate the IRC are pastel colors and it lacks the richest saturated colors. However, ironically, the most abrupt changes in color occur in saturated colors. In addition, the use of only 8 colors to calculate the IRC provides a very poor set of colors taking into account the range of colors present in the visible spectrum.

Another common misunderstanding is that a high IRC value means that the light source will reproduce all of the colors properly. But this is not the case. The IRC is measured only with  source of reference that is either the curve of a Black Body below 5000K or a source of Daylight CIE above 5000K. The reference should be the closest in chromaticity (color) to the source being tested. Otherwise, the comparison does not make sense. Comparing the IRC of two light sources with very different color temperatures makes no sense.


Soon we will hear about the CFI (color fidelity index/color fidelity index) instead of the CRI (color rendering index /color rendering index) and the color saturation index (Gamut index)


Many manufacturers use white LEDs with a wide spectrum and do not try to inflate artificial peaks that match the eight color samples in CRI. Due to these broad spectrums, the Rf and CRI index result of TM-30-15 are expected to be similar. In fact, when using the TM-30-15 method, we find that most products have CRI and Rf particles that are very similar, differing by only 1 to 2 points.


Want new articles before they get published?
Subscribe to our awesome Newsletter!