ΔE 8.0, close: similar, with a visible difference side by side. Arbuckles Brown is a little darker, more saturated than Obsidian Skin.
Usually, if you are not matching paint already on the model. Close match (ΔE 8). Arbuckles Brown is a little darker, more saturated than Obsidian Skin.
The same difference applies the other way round: Obsidian Skin is a little lighter, more muted.
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 Obsidian Skin on the colour wheel See Arbuckles Brown on the colour wheel
All matches: Obsidian Skin equivalents · Arbuckles Brown equivalents