Advanced Flesh Tone vs Barbarian Skin

How close are they?

ΔE 15.1, loose: different enough that you should pick on purpose. Barbarian Skin is a little darker, more saturated than Advanced Flesh Tone.

Can I use Barbarian Skin instead of Advanced Flesh Tone?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 15). Barbarian Skin is a little darker, more saturated than Advanced Flesh Tone.

Can I use Advanced Flesh Tone instead of Barbarian Skin?

The same difference applies the other way round: Advanced Flesh Tone is a little lighter, more muted.

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.