ΔE 10.2, fair: the same colour family, but not a straight swap. Karak Stone is a little lighter, more saturated, cooler than Pure Filth.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 10). Karak Stone is a little lighter, more saturated, cooler than Pure Filth.
The same difference applies the other way round: Pure Filth is a little darker, more muted, 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 Pure Filth on the colour wheel See Karak Stone on the colour wheel
All matches: Pure Filth equivalents · Karak Stone equivalents