ANSI/IES TM-30-20, an American National Standard method for evaluating light source color rendition that is published by the Illuminating Engineering Society, is a system of several related measures and graphics that can be used together to effectively evaluate and communicate a light source’s color rendering properties. The development of the method involved synthesizing multiple related research efforts and combining ideas into a single, cohesive system of objective information that can be used to aid decision-making processes, such as finding the preferred light source for a given application or evaluating the tradeoffs between efficacy and color rendering.

This tutorial article provides a comprehensive overview of the development and use of ANSI/IES TM-30-20. Five years since its initial publication, TM-30 is increasingly used by lighting producers, specifiers, and researchers due to its superior accuracy and the expanded scope of provided information compared to predecessor tools for assessing color rendition. Making the most of these improvements requires people who use the method to be more knowledgeable and intentional, and this tutorial consolidates a range of information to assist with best practices. The article, arranged as a series of questions, includes information about:

  • The development of the standard
  • Color rendering fundamentals
  • TM-30 measures and their meaning
  • TM-30 calculation details
  • Application of TM-30.

The document does not provide instructions for performing TM-30 calculations, which is the purpose of the ANSI/IES TM-30-20 standard, which is freely available.

Tutorial: Background and Guidance for Using the ANSI/IES TM-30 Method for Evaluating Light Source Color Rendition