Code 1633 (Brittany Blue) reflects 61.27% of incident D65 light. Measured in CAM16-UCS uniform space, Benjamin Moore Brittany Blue (1633) registers J'=84.7, a'=-6.50, and b'=-3.42 with HSL (188°, 14%, 79%) and Helmholtz-Kohlrausch perceived value 83 L*_HK. Because 1633 carries a*=-4.01 red-green and b*=-2.51 yellow-blue balance at chroma C*=4.73, Brittany Blue projects a cool cool coastal blue-grey character across drywall and millwork.
Thermal lighting shifts Benjamin Moore 1633 predictably. Under 5000K noon daylight, Brittany Blue (1633) holds its native #CBCFC9 swatch; at 4000K cool office LED, 1633 adapts to #D1CDC1; at 3500K halogen, Brittany Blue transitions to #D7CCBB; at 3000K residential LED, 1633 warms to #DDCBB6; and under 2700K evening bulbs, Brittany Blue (1633) settles at #E1C9B2.
When cross-matching Benjamin Moore Brittany Blue (1633, #C3D0D2), Behr Alice White (MQ3-58, #C2CED2, LRV 60%) scores ΔE2000=1.3 and CAM16=1.35, followed by Ash Blue (N470-1, ΔE=1.78). In Sherwin-Williams, Tradewind (SW 6218, #C2CFCF, LRV 60.52%) achieves ΔE2000=1.08 ahead of Sleepy Blue (SW 6225, ΔE=1.53). Coordinate 1633 with Snow White (OC-66) ceilings, Misty Gray (2124-60) trim, Patriotic White (2135-70) hallways, and Snow White (2122-70) accents.