Black Smoke, White Smoke: How the Vatican Signals Decisions on a New Pope

In a tradition that scholars date to the 19th century, smoke released from a chimney will be colored white if the cardinals have made a decision, or black if they remain deadlocked.

source https://www.nytimes.com/2025/05/07/world/europe/black-smoke-white-smoke-vatican-pope-vote-conclave.html