Pyrotechnic chemistry drives the Vatican’s recipes for the black and white smoke used to announce papal election outcomes

Roman Catholic cardinals will begin the task on Wednesday of electing a new pope, locking themselves away from the world until they choose the man they hope can unite a diverse but divided global Church.

As a fireworks expert tests the Vatican's contemporary system for "holy smoke," Catholic cardinals mull their divergent priorities for Pope Francis' successor.

The papal conclave, the secretive election process to elect the next leader of the Roman Catholic Church, commences on Wednesday.

Roman Catholic cardinals from across the globe are heading to the Sistine Chapel to choose a new pope, who will set the moral compass for the Church’s 1.4 billion faithful and become a reference point for much of the world.

The 133 cardinal electors due to choose a successor to the late Pope Francis gathered for a final Mass on Wednesday morning, just hours before they were to launch the secretive, centuries-old ritual known as the conclave to pick a new pontiff.