Kraken Skin vs Rotten Green

How close are they?

ΔE 22.5, loose: different enough that you should pick on purpose. Rotten Green is noticeably darker, warmer than Kraken Skin.

Can I use Rotten Green instead of Kraken Skin?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 22). Rotten Green is noticeably darker, warmer than Kraken Skin.

Can I use Kraken Skin instead of Rotten Green?

The same difference applies the other way round: Kraken Skin is noticeably lighter, 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.