Iron Hands Steel vs Dwarven Iron

How close are they?

ΔE 6.7, close: similar, with a visible difference side by side. Dwarven Iron is a little darker than Iron Hands Steel.

Can I use Dwarven Iron instead of Iron Hands Steel?

Usually, if you are not matching paint already on the model. Close match (ΔE 7). Dwarven Iron is a little darker than Iron Hands Steel.

Can I use Iron Hands Steel instead of Dwarven Iron?

The same difference applies the other way round: Iron Hands Steel is a little 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.