Mortarion Green Clear vs Green

How close are they?

ΔE 19.0, loose: different enough that you should pick on purpose. Green is noticeably darker, more muted, cooler than Mortarion Green Clear.

Can I use Green instead of Mortarion Green Clear?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 19). Green is noticeably darker, more muted, cooler than Mortarion Green Clear.

Can I use Mortarion Green Clear instead of Green?

The same difference applies the other way round: Mortarion Green Clear is noticeably lighter, more saturated, 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.