Screaming Bell vs Bullion

How close are they?

ΔE 17.9, loose: different enough that you should pick on purpose. Bullion is noticeably lighter, more saturated, cooler than Screaming Bell.

Can I use Bullion instead of Screaming Bell?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 18). Bullion is noticeably lighter, more saturated, cooler than Screaming Bell.

Can I use Screaming Bell instead of Bullion?

The same difference applies the other way round: Screaming Bell is noticeably darker, more muted, warmer.

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.