Forest Green vs Dark Green

How close are they?

ΔE 11.6, fair: the same colour family, but not a straight swap. Dark Green is noticeably lighter than Forest Green.

Can I use Dark Green instead of Forest Green?

Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 12). Dark Green is noticeably lighter than Forest Green.

Can I use Forest Green instead of Dark Green?

The same difference applies the other way round: Forest Green is noticeably darker.

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.