Code S400-1 (At Ease) reflects 83% of incident D65 light. Measured in CAM16-UCS uniform space, Behr At Ease (S400-1) registers J'=94.2, a'=-5.15, and b'=4.19 with HSL (92°, 28%, 91%) and Helmholtz-Kohlrausch perceived value 93.9 L*_HK. Because S400-1 carries a*=-4.62 red-green and b*=5.48 yellow-blue balance at chroma C*=7.17, At Ease projects a warm soft green-beige character across drywall and millwork.
Thermal lighting shifts Behr S400-1 predictably. Under 5000K noon daylight, At Ease (S400-1) holds its native #EFECD8 swatch; at 4000K cool office LED, S400-1 adapts to #F7EBCE; at 3500K halogen, At Ease transitions to #FDEAC8; at 3000K residential LED, S400-1 warms to #FFE8C2; and under 2700K evening bulbs, At Ease (S400-1) settles at #FFE6BF.
When cross-matching Behr At Ease (S400-1, #E7EEE1), Benjamin Moore Tint Of Mint (851, #EAEFDF, LRV 84.66%) scores ΔE2000=1.38 and CAM16=1.33, followed by Woodland White (463, ΔE=1.86). In Sherwin-Williams, White Mint (SW 6441, #E0E7DA, LRV 78.12%) achieves ΔE2000=1.51 ahead of Spinach White (SW 6434, ΔE=1.73). Coordinate S400-1 with Ultra Pure White (50) ceilings, Celestial Glow (PWN-36) trim, Mild Mint (PPU11-12) hallways, and Riverdale (N410-3) accents.