ΔE 22.2, loose: different enough that you should pick on purpose. Pure Filth is noticeably darker, more muted, cooler than Hearthborn.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 22). Pure Filth is noticeably darker, more muted, cooler than Hearthborn.
The same difference applies the other way round: Hearthborn is noticeably lighter, 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 Hearthborn on the colour wheel See Pure Filth on the colour wheel
All matches: Hearthborn equivalents · Pure Filth equivalents