Medium Drab vs Forest Green

How close are they?

ΔE 16.0, loose: different enough that you should pick on purpose. Forest Green is a little darker, more saturated, cooler than Medium Drab.

Can I use Forest Green instead of Medium Drab?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 16). Forest Green is a little darker, more saturated, cooler than Medium Drab.

Can I use Medium Drab instead of Forest Green?

The same difference applies the other way round: Medium Drab is a little lighter, more muted, 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.