Field Blue vs Blue Green

How close are they?

ΔE 9.3, close: similar, with a visible difference side by side. Blue Green is more muted, warmer than Field Blue.

Can I use Blue Green instead of Field Blue?

Usually, if you are not matching paint already on the model. Close match (ΔE 9). Blue Green is more muted, warmer than Field Blue.

Can I use Field Blue instead of Blue Green?

The same difference applies the other way round: Field Blue 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.