Canopy Green vs Rotten Green

How close are they?

ΔE 20.0, loose: different enough that you should pick on purpose. Rotten Green is noticeably darker, more muted than Canopy Green.

Can I use Rotten Green instead of Canopy Green?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 20). Rotten Green is noticeably darker, more muted than Canopy Green.

Can I use Canopy Green instead of Rotten Green?

The same difference applies the other way round: Canopy Green is noticeably lighter, 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.