The election of a new pope is announced with smoke: what do the colours mean, and how are they made?

By Clare Johnson

For nearly 800 years the Catholic Church has utilised the process of the conclave to elect a new pope. “Conclave” means “with a key”, indicating the cardinal-electors are locked up with a key to conduct their deliberations.

With no direct communication to the outside world, a key feature of the papal election process is the use of smoke to signal the result of ballots and to announce the election of a new pope.

Black smoke means a new pope has not been elected. White smoke means there is a new pope.

So where does this tradition come from – and how do they achieve the different coloured smoke?

Sending messages with smoke

Smoke signals are one of the oldest forms of long-distance communication between humans. For millennia, smoke signals have been used to indicate danger, to call for a gathering of tribes/nations, to transmit news and to warn of enemy invasions