ΔE 12.5, fair: the same colour family, but not a straight swap. Nocturnal Red is a little lighter, more saturated, cooler than Brown Leather.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 13). Nocturnal Red is a little lighter, more saturated, cooler than Brown Leather.
The same difference applies the other way round: Brown Leather is a little darker, more muted, warmer.
ΔE is the colour difference between our two swatch estimates: under about 6 is close, over about 15 is loose. Real paints also differ in finish, coverage and how they thin, so test before you commit.
See Brown Leather on the colour wheel See Nocturnal Red on the colour wheel
All matches: Brown Leather equivalents · Nocturnal Red equivalents