TM-30 Leaves Room for a New Industry-Wide Standard

The CRI (Color Rendering Index), developed by the International Commission on Illumination, has been used for half a century as a method of evaluating a light source’s color rendering properties. The CRI, however, has been unchanged for 40 years and is purely for evaluating color fidelity, which means its values work by comparing an object’s color appearance to how it looks under a specific illumination source. It does not consider other color qualities such as gamut.

After extensive research, the International Engineering Society has designed a new metric, the TM-30-15, or TM-30 for short, to remedy these shortcomings and provide a more comprehensive system to effectively evaluate a light source’s color rendering properties. It consists of multiple components, with the three most notable being the Fidelity Index, Gamut Index and Color Vector Graphic. The Color Fidelity Index, much like the CRI, can aid in determining the degree of similarity for a color or colors rendered by a test source and a reference condition. It does differ in some ways from the older index, namely, it considers 99 samples rather than the CRI’s eight and is not unfair to light sources that increase red chroma. The Color Gamut is applicable to the area enclosed by points in a chromaticity diagram. It can, however, have numerous meanings throughout color industries. As for the Color Vector Graphic, this refers to a visual graph that shows chroma and hue shifts for every color. It allows users to easily see which kinds of colors have more or less saturation when comparing them under a test source and reference illuminant.

The broad capabilities of the TM-30 include finding the preferred light source for a given application and increasing availability of data for characterization. The color rendering aptitudes are beneficial to specifiers, manufactures and researchers alike, though it remains to be seen if they will make the switch. The International Commission on Illumination is making new color rendering methods which could replace the CRI in time. But for now, it is ultimately up to those in the industry to adopt the TM-30 or continue to rely on the 40-year-old CRI.

Konica Minolta Sensing offers a wide variety of color and light measurement products. They can measure a large range of substances and are the perfect complement to one of these indexes.