Final answer:
The Delphic Sibyl on the Sistine Chapel ceiling, painted by Michelangelo, exhibits monumental form, powerful arms, and a harmonious posture. The Libyan Sibyl, also featured, is portrayed with dynamic tension in a contorted position. Both figures contribute to the ceiling's complex religious and artistic iconography.
Step-by-step explanation:
The form of the Delphic Sibyl, as detailed from the Sistine Chapel, showcases Michelangelo's skill in creating a sense of monumentality, combined with graceful proportions and a harmonious posture. This figure of the Delphic Sibyl is characterized by her powerful arms and imposing physique, bringing a three-dimensional effect to the viewer's space. Michelangelo's depiction is reminiscent of his David, with a watchful expression and a balance between strength and elegance. The Delphic Sibyl, along with other sibyls and prophets on the ceiling, prefigures the coming of the Christian Messiah and adds to the overall iconography of this masterpiece.
In contrast, the Libyan Sibyl is depicted in a contorted yet graceful position, demonstrating a sprezzatura that later influenced Mannerist artists. The Libyan Sibyl's portrayal in a regal orange dress, lifting a heavy book, showcases the illusion of tension created through the twisting of her body and the flowing of her garments, which is testament to Michelangelo's mastery in painting.
The frescoes on the Sistine Chapel ceiling include iconographical elements like the Sibyls, as well as stories from the Old Testament, scenes from Genesis, and figures like ignudi that add to the richness of the imagery. Michelangelo employed the fresco technique, painting on wet plaster to create these enduring images.