Sand vs Fairy Flesh

How close are they?

ΔE 15.4, loose: different enough that you should pick on purpose. Fairy Flesh is noticeably lighter, more saturated than Sand.

Can I use Fairy Flesh instead of Sand?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 15). Fairy Flesh is noticeably lighter, more saturated than Sand.

Can I use Sand instead of Fairy Flesh?

The same difference applies the other way round: Sand is noticeably darker, 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.