Dark Soviet Khaki vs Thornwood Green

How close are they?

ΔE 15.1, loose: different enough that you should pick on purpose. Thornwood Green is noticeably lighter, cooler than Dark Soviet Khaki.

Can I use Thornwood Green instead of Dark Soviet Khaki?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 15). Thornwood Green is noticeably lighter, cooler than Dark Soviet Khaki.

Can I use Dark Soviet Khaki instead of Thornwood Green?

The same difference applies the other way round: Dark Soviet Khaki is noticeably darker, warmer.

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.