ΔE 10.5, fair: the same colour family, but not a straight swap. Emperor's Children is more saturated, cooler than Old Red.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 10). Emperor's Children is more saturated, cooler than Old Red.
The same difference applies the other way round: Old Red is 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 Old Red on the colour wheel See Emperor's Children on the colour wheel
All matches: Old Red equivalents · Emperor's Children equivalents