The election itself is shrouded in secrecy, with cardinals forbidden from communicating with the outside world what happened during the voting in the conclave behind the frescoed walls of the Sistine Chapel.

St. John Paul II rewrote the regulations on papal elections in a 1996 document that remains largely in force, though Pope Benedict XVI amended it twice before he resigned. Here is what happens when a pope dies, a period known as the “sede vacante,” or the “vacant See.”

After the ballots are pierced, they are burned in a cylindrical stove at the end of the voting session. Black smoke from the Sistine Chapel chimney means no decision; white smoke signals the cardinals have chosen a pope and that he has accepted.

Chemical cartridges are added to ensure there is no confusion over the color. To produce black smoke, a cartridge containing potassium perchlorate, anthracene — the component of coal tar — and sulphur is burned with the ballots. For white smoke, a cartridge of potassium chlorate, lactose and chloroform resin is burned with the ballots.

Bells also are rung to signal the election of a pope for further clarity.

The new pope is introduced from the loggia overlooking St. Peter’s Square with the words, “Habemus Papam!” (“We have a pope!”) and his chosen papal name. The new pope then emerges and gives his first blessing.

– With Associated Press