Night Sky vs Dark Green BS381C/641

How close are they?

ΔE 7.2, close: similar, with a visible difference side by side. Dark Green BS381C/641 is more muted than Night Sky.

Can I use Dark Green BS381C/641 instead of Night Sky?

Usually, if you are not matching paint already on the model. Close match (ΔE 7). Dark Green BS381C/641 is more muted than Night Sky.

Can I use Night Sky instead of Dark Green BS381C/641?

The same difference applies the other way round: Night Sky is more saturated.

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.