Karak Stone vs Flesh

How close are they?

ΔE 15.3, loose: different enough that you should pick on purpose. Flesh is a little lighter, more saturated, warmer than Karak Stone.

Can I use Flesh instead of Karak Stone?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 15). Flesh is a little lighter, more saturated, warmer than Karak Stone.

Can I use Karak Stone instead of Flesh?

The same difference applies the other way round: Karak Stone is a little darker, 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.