Dwarven Iron vs Obsidian Black

How close are they?

ΔE 11.2, fair: the same colour family, but not a straight swap. Obsidian Black is noticeably darker than Dwarven Iron.

Can I use Obsidian Black instead of Dwarven Iron?

Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 11). Obsidian Black is noticeably darker than Dwarven Iron.

Can I use Dwarven Iron instead of Obsidian Black?

The same difference applies the other way round: Dwarven Iron is noticeably lighter.

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.