Resurrection Flesh vs Dark Sand

How close are they?

ΔE 17.3, loose: different enough that you should pick on purpose. Dark Sand is a little lighter, much more saturated, cooler than Resurrection Flesh.

Can I use Dark Sand instead of Resurrection Flesh?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 17). Dark Sand is a little lighter, much more saturated, cooler than Resurrection Flesh.

Can I use Resurrection Flesh instead of Dark Sand?

The same difference applies the other way round: Resurrection Flesh is a little darker, much more muted, 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.