ΔE 12.6, fair: the same colour family, but not a straight swap. Kislev Flesh is a little darker, warmer than Basic Skin.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 13). Kislev Flesh is a little darker, warmer than Basic Skin.
The same difference applies the other way round: Basic Skin is a little lighter, 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.
See Basic Skin on the colour wheel See Kislev Flesh on the colour wheel
All matches: Basic Skin equivalents · Kislev Flesh equivalents