Every inch of the Sistine Chapel is painted in fresco. The word fresco refers to both technique and result. This type of wall painting is created using a fresh and humid preparation layer. The coating was made of lime or gypsum mortar, and artists had to add the colors while the coating was still wet. Through a series of chemical reactions, the color pigments mixed with water would merge with the coating. This is what made fresco most resistant. Painting fresco is a difficult feat to accomplish because the amount of time available to complete the actual painting is greatly reduced by the drying speed of the coating—on average, 6 hours a day. Once it is dry, no more chemical reaction can be induced. Let’s note here that Michelangelo did his frescoed ceiling alone and without electricity!