Pharaoh Guard vs Kraken Green

How close are they?

ΔE 18.5, loose: different enough that you should pick on purpose. Kraken Green is noticeably darker, more muted than Pharaoh Guard.

Can I use Kraken Green instead of Pharaoh Guard?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 18). Kraken Green is noticeably darker, more muted than Pharaoh Guard.

Can I use Pharaoh Guard instead of Kraken Green?

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

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.