Bad Moon Yellow vs Sulfur Yellow

How close are they?

ΔE 8.3, close: similar, with a visible difference side by side. Sulfur Yellow is a little lighter, more saturated than Bad Moon Yellow.

Can I use Sulfur Yellow instead of Bad Moon Yellow?

Usually, if you are not matching paint already on the model. Close match (ΔE 8). Sulfur Yellow is a little lighter, more saturated than Bad Moon Yellow.

Can I use Bad Moon Yellow instead of Sulfur Yellow?

The same difference applies the other way round: Bad Moon Yellow is a little darker, more muted.

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.