To produce the dramatic black smoke during the 2013 conclave, technicians burned a mixture of potassium perchlorate, anthracene, and sulfur.

What does the white and black smoke mean during the conclave? There are multiple voting rounds during a papal conclave. A pope is elected when a candidate receives a two-thirds majority of the votes.

The smoke’s color is dictated by the particle color, which means white and black colored smoke result from waste products other than carbon dioxide, which is colorless.