Mortarion Green Clear vs Ordic Olive

How close are they?

ΔE 22.4, loose: different enough that you should pick on purpose. Ordic Olive is a little darker, much more muted, warmer than Mortarion Green Clear.

Can I use Ordic Olive instead of Mortarion Green Clear?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 22). Ordic Olive is a little darker, much more muted, warmer than Mortarion Green Clear.

Can I use Mortarion Green Clear instead of Ordic Olive?

The same difference applies the other way round: Mortarion Green Clear is a little lighter, much more saturated, cooler.

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.