Code HDC-NT-20 (Cotton Grey) reflects 61% of incident D65 light. Measured in CAM16-UCS uniform space, Behr Cotton Grey (HDC-NT-20) registers J'=84.5, a'=-0.10, and b'=3.71 with HSL (39°, 13%, 79%) and Helmholtz-Kohlrausch perceived value 82.6 L*_HK. Because HDC-NT-20 carries a*=0.15 red-green and b*=5.09 yellow-blue balance at chroma C*=5.09, Cotton Grey projects a warm warm yellow-cream character across drywall and millwork.
Thermal lighting shifts Behr HDC-NT-20 predictably. Under 5000K noon daylight, Cotton Grey (HDC-NT-20) holds its native #D8CBBB swatch; at 4000K cool office LED, HDC-NT-20 adapts to #DEC9B2; at 3500K halogen, Cotton Grey transitions to #E3C8AD; at 3000K residential LED, HDC-NT-20 warms to #E9C6A8; and under 2700K evening bulbs, Cotton Grey (HDC-NT-20) settles at #EEC5A5.
When cross-matching Behr Cotton Grey (HDC-NT-20, #D1CCC3), Benjamin Moore Collingwood (859, #D3CEC4, LRV 62.09%) scores ΔE2000=0.66 and CAM16=0.73, followed by Collingwood (OC-28, ΔE=0.66). In Sherwin-Williams, Agreeable Gray (SW 7029, #D1CBC1, LRV 60.23%) achieves ΔE2000=0.6 ahead of Gossamer Veil (SW 9165, ΔE=0.66). Coordinate HDC-NT-20 with Bakery Box (BL-W9) ceilings, Maui Mist (BL-W10) trim, Villa White (PWN-51) hallways, and Ultra Pure White® (PR-W15) accents.