Practice without science is a ship without rudder or compass
Perspective as the guide and gateway of painting; young leaves and why plant shadows are never black
Written in red chalk (a sanguigna), the page opens with Leonardo's warning on the error of those who practise without science: such a person is like a helmsman who boards a ship without rudder or compass and never knows where he is going. Practice must be built upon good theory, of which perspective is the guide and gateway, and without it nothing is done well in painting. He then turns to plants, noting that young plants have more transparent leaves and smoother bark than old ones (above all the walnut, and paler in May than September), and that plant shadows are never wholly black because where air penetrates there can be no darkness. A marginal note in the upper right reminds the reader to consult Horace's Ars Poetica first.
On this page
The error of practice without science
Those who fall in love with practice without science are like the helmsman who boards a ship without rudder or compass and is never certain where he is going. Practice must always be built upon good theory, of which perspective is the guide and gateway; and without it nothing is done well in matters of painting.
Young plants: more transparent leaves and smoother bark
Young plants have more transparent leaves and smoother bark than old ones, and above all the walnut. Their leaves are clearer and paler in May than in September.
Why the shadows of plants are never black
The shadows of plants are never black, because wherever the air penetrates there cannot be darkness.