Specify LED sources with CRI ≥95 (preferably 97+), TM-30 Rf ≥95, and Rg between 98-102 (neutral gamut). Request spectral power distribution (SPD) data from manufacturers. Avoid sources with gaps in the spectrum even if CRI is high. Specify CCT based on artwork period: 3000K for Old Masters (approximates candlelight/natural light), 4000K for modern work (approximates north light). Verify UV-free output (no emission below 400nm). Consider Gamut Index (TM-30) for specific color families if collection has known dominant hues.