ΔE 10.3, fair: the same colour family, but not a straight swap. Forest Skin is a little lighter, more saturated than Walnut.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 10). Forest Skin is a little lighter, more saturated than Walnut.
The same difference applies the other way round: Walnut is a little darker, 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 Walnut on the colour wheel See Forest Skin on the colour wheel
All matches: Walnut equivalents · Forest Skin equivalents