ΔE 10.6, fair: the same colour family, but not a straight swap. Martian Ironearth is more muted, warmer than Skin INK. They are different kinds of paint: AK Interactive Skin INK is an ink, glaze or transparent paint and Citadel Martian Ironearth is a technical paint or medium, so they won’t behave the same on the model even where the colour is close.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 11). Martian Ironearth is more muted, warmer than Skin INK. They are different kinds of paint.
The same difference applies the other way round: Skin INK is more saturated, 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 Skin INK on the colour wheel See Martian Ironearth on the colour wheel
All matches: Skin INK equivalents · Martian Ironearth equivalents