Ratskin Flesh vs Quicksand Brown

How close are they?

ΔE 17.4, loose: different enough that you should pick on purpose. Quicksand Brown is noticeably darker, more saturated, warmer than Ratskin Flesh.

Can I use Quicksand Brown instead of Ratskin Flesh?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 17). Quicksand Brown is noticeably darker, more saturated, warmer than Ratskin Flesh.

Can I use Ratskin Flesh instead of Quicksand Brown?

The same difference applies the other way round: Ratskin Flesh 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.