Da Vinci Notes #24 - Illusions

 

ON PAINTING.

 

Variability of the eye.

 

1st. The pupil of the eye contracts, in proportion to the increase

of light which is reflected in it. 2nd. The pupil of the eye expands

in proportion to the diminution in the day light, or any other

light, that is reflected in it.

 

3rd. The eye perceives and recognises the objects of its vision

with greater intensity in proportion as the pupil is more widely

dilated; and this can be proved by the case of nocturnal animals,

such as cats, and certain birds--as the owl and others--in which

the pupil varies in a high degree from large to small, &c., when

in the dark or in the light.

 

4th. The eye [out of doors] in an illuminated atmosphere sees

darkness behind the windows of houses which [nevertheless] are

light. 5th. All colours when placed in the shade appear of an equal

degree of darkness, among themselves. 6th. But all colours when

placed in a full light, never vary from their true and essential