IJN Hull Color/Maizuru vs Dark Ghost Gray

How close are they?

ΔE 7.2, close: similar, with a visible difference side by side. Dark Ghost Gray is a little darker than IJN Hull Color/Maizuru.

Can I use Dark Ghost Gray instead of IJN Hull Color/Maizuru?

Usually, if you are not matching paint already on the model. Close match (ΔE 7). Dark Ghost Gray is a little darker than IJN Hull Color/Maizuru.

Can I use IJN Hull Color/Maizuru instead of Dark Ghost Gray?

The same difference applies the other way round: IJN Hull Color/Maizuru is a little lighter.

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.