IES Symposium Summary

If you missed IES Research Symposium III Light + Color you missed an exciting (for color geeks) few days. It would take too long to relate everything that was discussed, but here are some key highlights.

• TM-30-15 is seeing broader acceptance throughout the industry. In an exciting development, it seems that the CIE is going to endorse TM-30 Rf after a few changes are made. The expectation is that the industry will then begin a rapid movement toward using Rf instead of CRI Ra, and that eventually CRI will be withdrawn. Unfortunately, the CIE is notoriously slow, so there is no timeline for their formal endorsement of TM-30. Maybe next year?
• Manufacturers are resolving the spectral deficiencies that result from using a limited number of LEDs in both color mixing and color temperature tuning products. Their solution is to move from two and three color systems to systems using four or five independently controlled colors of LEDs.
• Color preference was a big topic with no resolution. One complaint of both CRI and TM-30 is that they penalize light sources that deviate from the reference source even if many people prefer the deviation. Of course, Ra and Rf are both fidelity metrics, so they must penalize such deviations.   We have strong evidence that people prefer light sources that slightly increase the saturation of objects, and that people prefer light sources that include somewhat more red than the reference sources. However, because the amount of deviation that is preferred is application dependent, a single, all-purpose metric for rating color preference seems to be unattainable.