Dark Soviet Khaki vs Field Grey

How close are they?

ΔE 7.1, close: similar, with a visible difference side by side. Field Grey is more muted than Dark Soviet Khaki.

Can I use Field Grey instead of Dark Soviet Khaki?

Usually, if you are not matching paint already on the model. Close match (ΔE 7). Field Grey is more muted than Dark Soviet Khaki.

Can I use Dark Soviet Khaki instead of Field Grey?

The same difference applies the other way round: Dark Soviet Khaki 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.