Pharaoh Guard vs Dark Evergreen

How close are they?

ΔE 19.3, loose: different enough that you should pick on purpose. Dark Evergreen is noticeably darker, more muted, warmer than Pharaoh Guard.

Can I use Dark Evergreen instead of Pharaoh Guard?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 19). Dark Evergreen is noticeably darker, more muted, warmer than Pharaoh Guard.

Can I use Pharaoh Guard instead of Dark Evergreen?

The same difference applies the other way round: Pharaoh Guard is noticeably lighter, 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.