Bloodreaver Flesh vs Brown

How close are they?

ΔE 7.1, close: similar, with a visible difference side by side. Brown is cooler than Bloodreaver Flesh.

Can I use Brown instead of Bloodreaver Flesh?

Usually, if you are not matching paint already on the model. Close match (ΔE 7). Brown is cooler than Bloodreaver Flesh.

Can I use Bloodreaver Flesh instead of Brown?

The same difference applies the other way round: Bloodreaver Flesh is 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.