Imperial Navy vs Ritterlich Blue

How close are they?

ΔE 9.9, close: similar, with a visible difference side by side. Ritterlich Blue is more muted, cooler than Imperial Navy.

Can I use Ritterlich Blue instead of Imperial Navy?

Usually, if you are not matching paint already on the model. Close match (ΔE 10). Ritterlich Blue is more muted, cooler than Imperial Navy.

Can I use Imperial Navy instead of Ritterlich Blue?

The same difference applies the other way round: Imperial Navy is more saturated, 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.