Sistine Chapel ceiling of the Sistine Chapel. At the outset, the plaster, "intonaco", began to grow mold because it was too wet. Michelangelo had to remove it and start again. He then tried a new formula created by one of his assistants, Jacopo l'Indaco, which resisted mold and entered the Italian building tradition. Because he was painting "fresco", the plaster was laid in a new section every day, called a "giornata". At the beginning of each session, the edges would be scraped away and a new area laid down. The edges between "giornate" remain slightly visible; thus, they give a good idea of
Sistine Chapel ceiling God, he was swallowed by a "mighty fish". He spent three days in its belly and was eventually spewed up on dry land where he went about God's business. Jonah was thus seen as presaging Jesus, who having died by crucifixion, spent part of three days in a tomb and was raised on the third day. So, on the ceiling of the Sistine Chapel, Jonah, with the "great fish" beside him and his eyes turned towards God the Creator, represents a "portent" of the Passion and Resurrection of Christ. The Jonah figure placed right over the altar activated the Passion