Boone Tan vs Flat Flesh

How close are they?

ΔE 18.6, loose: different enough that you should pick on purpose. Flat Flesh is noticeably darker, more saturated, warmer than Boone Tan.

Can I use Flat Flesh instead of Boone Tan?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 19). Flat Flesh is noticeably darker, more saturated, warmer than Boone Tan.

Can I use Boone Tan instead of Flat Flesh?

The same difference applies the other way round: Boone Tan is noticeably lighter, more muted, cooler.

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.