Commando Green vs Viridian Green

How close are they?

ΔE 16.0, loose: different enough that you should pick on purpose. Viridian Green is noticeably lighter, more muted, cooler than Commando Green.

Can I use Viridian Green instead of Commando Green?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 16). Viridian Green is noticeably lighter, more muted, cooler than Commando Green.

Can I use Commando Green instead of Viridian Green?

The same difference applies the other way round: Commando Green is noticeably darker, more saturated, 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.