Plague Toad Venom vs Moon Yellow

How close are they?

ΔE 16.7, loose: different enough that you should pick on purpose. Moon Yellow is a little lighter, more saturated, warmer than Plague Toad Venom.

Can I use Moon Yellow instead of Plague Toad Venom?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 17). Moon Yellow is a little lighter, more saturated, warmer than Plague Toad Venom.

Can I use Plague Toad Venom instead of Moon Yellow?

The same difference applies the other way round: Plague Toad Venom is a little darker, more muted, 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.