Flat Brown vs Black Red

How close are they?

ΔE 10.9, fair: the same colour family, but not a straight swap. Black Red is a little darker, cooler than Flat Brown.

Can I use Black Red instead of Flat Brown?

Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 11). Black Red is a little darker, cooler than Flat Brown.

Can I use Flat Brown instead of Black Red?

The same difference applies the other way round: Flat Brown is a little lighter, 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.