Marine Blue vs Triumphant Navy

How close are they?

ΔE 9.9, close: similar, with a visible difference side by side. Triumphant Navy is a little darker, more saturated, warmer than Marine Blue.

Can I use Triumphant Navy instead of Marine Blue?

Usually, if you are not matching paint already on the model. Close match (ΔE 10). Triumphant Navy is a little darker, more saturated, warmer than Marine Blue.

Can I use Marine Blue instead of Triumphant Navy?

The same difference applies the other way round: Marine Blue is a little lighter, more muted, 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.