Ghoul Green vs Zombie Skin

How close are they?

ΔE 38.0, loose: different enough that you should pick on purpose. Zombie Skin is a little lighter, much more muted, warmer than Ghoul Green.

Can I use Zombie Skin instead of Ghoul Green?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 38). Zombie Skin is a little lighter, much more muted, warmer than Ghoul Green.

Can I use Ghoul Green instead of Zombie Skin?

The same difference applies the other way round: Ghoul Green is a little darker, 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.