Olive Green vs Death World Forest

How close are they?

ΔE 15.4, loose: different enough that you should pick on purpose. Death World Forest is a little darker, much more saturated than Olive Green.

Can I use Death World Forest instead of Olive Green?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 15). Death World Forest is a little darker, much more saturated than Olive Green.

Can I use Olive Green instead of Death World Forest?

The same difference applies the other way round: Olive Green is a little lighter, much more muted.

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.