Plate Mail Metal vs Runefang Steel

How close are they?

ΔE 7.3, close: similar, with a visible difference side by side. Runefang Steel is a little lighter than Plate Mail Metal.

Can I use Runefang Steel instead of Plate Mail Metal?

Usually, if you are not matching paint already on the model. Close match (ΔE 7). Runefang Steel is a little lighter than Plate Mail Metal.

Can I use Plate Mail Metal instead of Runefang Steel?

The same difference applies the other way round: Plate Mail Metal is a little darker.

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.