Space Grey vs Stormfang

How close are they?

ΔE 6.3, close: similar, with a visible difference side by side. Stormfang is more saturated, cooler than Space Grey.

Can I use Stormfang instead of Space Grey?

Usually, if you are not matching paint already on the model. Close match (ΔE 6). Stormfang is more saturated, cooler than Space Grey.

Can I use Space Grey instead of Stormfang?

The same difference applies the other way round: Space Grey is more muted, warmer.

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.