Barbarian Flesh vs Bright Shadow Flesh

How close are they?

ΔE 6.3, close: similar, with a visible difference side by side. Bright Shadow Flesh is a little darker than Barbarian Flesh.

Can I use Bright Shadow Flesh instead of Barbarian Flesh?

Usually, if you are not matching paint already on the model. Close match (ΔE 6). Bright Shadow Flesh is a little darker than Barbarian Flesh.

Can I use Barbarian Flesh instead of Bright Shadow Flesh?

The same difference applies the other way round: Barbarian Flesh is a little lighter.

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.