Iron Wolf vs Greatcoat Grey

How close are they?

ΔE 7.0, close: similar, with a visible difference side by side. Greatcoat Grey is more muted, warmer than Iron Wolf.

Can I use Greatcoat Grey instead of Iron Wolf?

Usually, if you are not matching paint already on the model. Close match (ΔE 7). Greatcoat Grey is more muted, warmer than Iron Wolf.

Can I use Iron Wolf instead of Greatcoat Grey?

The same difference applies the other way round: Iron Wolf is more saturated, cooler.

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.