Disgusting Slime vs Yellow Green

How close are they?

ΔE 15.5, loose: different enough that you should pick on purpose. Yellow Green is more muted, warmer than Disgusting Slime.

Can I use Yellow Green instead of Disgusting Slime?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 16). Yellow Green is more muted, warmer than Disgusting Slime.

Can I use Disgusting Slime instead of Yellow Green?

The same difference applies the other way round: Disgusting Slime is 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.