Marine Blue vs Blue

How close are they?

ΔE 8.5, close: similar, with a visible difference side by side. Blue is a little darker, more saturated than Marine Blue.

Can I use Blue instead of Marine Blue?

Usually, if you are not matching paint already on the model. Close match (ΔE 9). Blue is a little darker, more saturated than Marine Blue.

Can I use Marine Blue instead of Blue?

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

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.