Muscles in Action and the Vice of Repeating Faces
How swelling muscles shorten sinews, and the fault of repeating movements and beauties in one scene
The page continues Leonardo's argument that the painter must understand which muscles, swelling, shorten which sinews, and which cords wrap the muscle, so as to become a varied and universal demonstrator of muscles through the varied actions of figures rather than repeating the same shapes in arms, backs, chest and legs. Two further chapters attack the defect of masters who repeat identical movements and identical facial beauties within one scene, since nature never repeats a face exactly. The greatest fault is making most faces resemble the painter's own; the page is neat text with no diagram.
On this page
Which muscle shortens which sinew
The knowing painter grasps which nerves cause a limb to move, which muscle by swelling shortens its sinew, and which cords, turned to fine cartilage, surround and gather the muscle. So he becomes a varied and universal demonstrator of muscles through the varied actions of the figures.
Masters who repeat the same faces (chap. 107)
It is a supreme defect to repeat the same movements in one scene and to make the beauties of faces always identical, since nature never repeats a face exactly. If all beauties of equal excellence returned to life they would outnumber the people of the present age, yet no two would precisely resemble each other.
The greatest defect: faces that resemble the master (chap. 108)
The greatest defect in painters is to repeat the same movements, faces and manners of drapery in one scene, and to make most faces resemble their master. Leonardo marvels at painters whose every figure seems a self-portrait, showing the maker's own actions and manner.