CRI, Rf, and the color-quality gap

What CRI can and cannot say

General CRI, often written Ra, averages a limited set of test colors under the source compared with a reference of similar color temperature. A value of 80 or 90 can support a practical first comparison. It does not guarantee that saturated red, skin, artwork, or food will look the way you expect.

The U.S. Department of Energy notes that 80 is a common minimum for interior lighting and 90 or higher indicates excellent color fidelity in the CRI framework. That remains a framework-specific statement, not proof that all products with the same number share the same spectrum.

Why Rf adds information

Newer systems such as IES TM-30 use a much larger color evaluation set and report fidelity as Rf alongside additional information about gamut and hue shifts. CIE’s 2025 position statement recommends gradually replacing the old general color rendering index with Rf while reporting both during a transition period.

That recommendation does not make CRI labels useless overnight. It does mean that a careful product comparison should look beyond one headline number when manufacturers publish fuller color data.

Make a small material test

Specifications narrow the field; samples resolve the room. Place competing lamps in the real fixture or a comparable temporary socket. Look at faces, red and blue objects, wood, paint, artwork, food, and neutral whites at the times you use the space.

Keep color temperature similar when comparing color fidelity. A cooler or warmer source can dominate perception and make it hard to isolate differences caused by spectral quality.

A score is a map. A material mock-up in the actual room is the journey.