Runefang Steel vs Silver Fox

How close are they?

ΔE 8.9, close: similar, with a visible difference side by side. Silver Fox is a little darker than Runefang Steel.

Can I use Silver Fox instead of Runefang Steel?

Usually, if you are not matching paint already on the model. Close match (ΔE 9). Silver Fox is a little darker than Runefang Steel.

Can I use Runefang Steel instead of Silver Fox?

The same difference applies the other way round: Runefang 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.