IES TM-30
IES TM-30 — IES Method for Evaluating Light Source Color Rendition
Definition
IES TM-30 is the modern IES method for evaluating color rendition of a light source. It supersedes the older CRI (Color Rendering Index) by reporting two scalars (Rf — fidelity, Rg — gamut) computed against 99 reference colors. Lighting professionals report TM-30 numbers alongside flicker numbers when characterizing an LED product.
Source overview
TM-30 evaluates a light source's color rendition by comparing its rendering of 99 carefully-chosen Color Evaluation Samples (CES) against a reference illuminant of equivalent CCT. It produces Rf (fidelity, 0–100, higher = closer to reference) and Rg (gamut, ~80–120, higher = more saturated than reference, lower = less saturated). TM-30 supersedes the older CRI Ra metric in modern lighting specifications and procurement.
The underlying standard is paywalled or otherwise not directly reproducible here. The text above is a plain-language summary written by Slick Engineering — not a verbatim quote. Authoritative source linked below.
Technical detail
TM-30 and flicker are independent properties of a light source — a lamp can score perfectly on Rf and still flicker badly. We list TM-30 in this glossary because lighting professionals often discuss it alongside flicker, and FlickerSpec product copy mentions it in passing.
FlickerSpec does not measure TM-30 directly — color rendition requires a calibrated spectrometer, not a phone camera. We reference TM-30 in the standards-cited list because professionals working with LED products typically need both flicker and color-rendition evidence.
Where it appears
- FlickerSpec Used here
Cited in FlickerSpec's standards list as a sibling lighting standard. FlickerSpec does not produce TM-30 measurements — see complementary instrumentation for color rendition.
Related terms
- IEEE 1789-2015
IEEE 1789-2015 is an IEEE recommended practice that defines low-risk and no-effect frequency / modulation-depth thresholds for current modul…
- Percent flicker
Percent flicker is the relative variation in light output of a source over one full modulation cycle, expressed as a percentage. 0% means no…