Charred Bone vs Pure Filth

How close are they?

ΔE 6.9, close: similar, with a visible difference side by side. Pure Filth is a little lighter, more saturated than Charred Bone.

Can I use Pure Filth instead of Charred Bone?

Usually, if you are not matching paint already on the model. Close match (ΔE 7). Pure Filth is a little lighter, more saturated than Charred Bone.

Can I use Charred Bone instead of Pure Filth?

The same difference applies the other way round: Charred Bone 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.