Stormfang vs Neutral Gray

How close are they?

ΔE 8.1, close: similar, with a visible difference side by side. Neutral Gray is a little darker, more muted than Stormfang.

Can I use Neutral Gray instead of Stormfang?

Usually, if you are not matching paint already on the model. Close match (ΔE 8). Neutral Gray is a little darker, more muted than Stormfang.

Can I use Stormfang instead of Neutral Gray?

The same difference applies the other way round: Stormfang is a little lighter, more saturated.

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.