ΔE 9.8, close: similar, with a visible difference side by side. Brown Ink is a little lighter, more muted, cooler than Warm Skin Tone. They are different kinds of paint: Army Painter Warm Skin Tone is a wash/shade and Formula P3 Brown Ink is an ink, glaze or transparent paint, so they won’t behave the same on the model even where the colour is close.
Usually, if you are not matching paint already on the model. Close match (ΔE 10). Brown Ink is a little lighter, more muted, cooler than Warm Skin Tone. They are different kinds of paint.
The same difference applies the other way round: Warm Skin Tone is a little darker, more saturated, 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.
See Warm Skin Tone on the colour wheel See Brown Ink on the colour wheel
All matches: Warm Skin Tone equivalents · Brown Ink equivalents