Runefang Steel vs Bright Silver

How close are they?

ΔE 8.3, close: similar, with a visible difference side by side. Bright Silver is a little lighter than Runefang Steel.

Can I use Bright Silver instead of Runefang Steel?

Usually, if you are not matching paint already on the model. Close match (ΔE 8). Bright Silver is a little lighter than Runefang Steel.

Can I use Runefang Steel instead of Bright Silver?

The same difference applies the other way round: Runefang Steel 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.