Hardened Carapace vs Abaddon Black

How close are they?

ΔE 11.6, fair: the same colour family, but not a straight swap. Abaddon Black is noticeably darker, more muted than Hardened Carapace.

Can I use Abaddon Black instead of Hardened Carapace?

Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 12). Abaddon Black is noticeably darker, more muted than Hardened Carapace.

Can I use Hardened Carapace instead of Abaddon Black?

The same difference applies the other way round: Hardened Carapace is noticeably lighter, more saturated.

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.