ΔE 18.0, loose: different enough that you should pick on purpose. Copper is a little lighter, much more saturated than Screaming Bell.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 18). Copper is a little lighter, much more saturated than Screaming Bell.
The same difference applies the other way round: Screaming Bell is a little darker, much 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.
See Screaming Bell on the colour wheel See Copper on the colour wheel
All matches: Screaming Bell equivalents · Copper equivalents