Page 281 - Art In The Age Of Exploration (Great Section on Chinese Art Ming Dynasty)

assigns the imprensiva (receptor of impressions) techniques of ray-tracing in modern computer all the diameter of the sky at mx. The angle d
to the first ventricle and identifies the second as graphics) and also regarded them as revealing makes little difference compared to c, because
the senso comune (common sense), in which the integral parts of the mathematical laws of nature the angles they subtend are not of such dis-
sensory impressions are compared and the facul- as whole. The laws decree that all effects decrease torted proportions as the others that are lower
ties of intellect, voluntary action, and imagination in a precisely proportional (that is, pyramidal) down, and d is deprived only of that part of the
are exercised. The final ventricle is deemed to be manner. The notes on the left-hand folio (13v) diameter that is between x and y. Although it
the house of memory. It is through this system explain that: acquires as much from the opposite side, never-
of outer and inner senses that the soul, which theless its line is of little strength because its
resides in the central ventricle, gains access to the Every shadow made by an opaque body smaller angle is smaller than the corresponding one.
knowledge of the world and can find true satisfac- than the source of light casts derivative shadows The angles e and i will be of diminished light,
tion, so that its "bodily prison" becomes bearable. tinged by the color of the original shadows. because they are not fully exposed, lacking the
The analysis of the coats of the brain by analogy The origin of the shadow ef is n, and it will be light ms and the light vx, and their angles will
to the skins of an onion is typical of Leonardo's tinged with its color. The origin of he is o, and be somewhat distorted Og will be the mini-
sense of the analogous natures of all the products it will be similarly tinged with its color... Fg is mum degree of light because it is not exposed
of creation. The layers are recorded correctly in the first degree of light, because there it is illu- to any part of the diameter of the light, and
the upper diagram as "hair, scalp, lacterous flesh, minated by all the window ad, and thus the Zky these are the lines that on the other side recon-
opaque body at m is of similar brightness.
pericranium, dura mater, pia mater, brain"— stitute a pyramid comparable to the pyramid
although in the lower diagram he inadvertently is a triangle which contains in itself the first c The apexes of these pyramids are aligned
reverses the pia and dura maters. M.K. degree of shadow, because the light ad does not and oriented toward each other along a straight
arrive within this triangle. Xh is the second
degree of shadow, because it is illuminated by line, which passes through the center of the
opaque body....
only a third of the window, that is to say cd
On the right hand folio (i4r), Leonardo informs The way that light strikes a surface, making the
us that: surface appear lightest where it strikes perpendic-
ularly and least light where it strikes a glancing
Every light which falls on opaque bodies blow, obeys the laws of 'percussion' in the same
ISO between equal angles produces the first degree way as a bouncing ball or current of water hitting
Leonardo da Vinci of brightness and that will be darker which a river bank. Leonardo did not intend these anal-
Florentine, 1452-1519 receives it by less equal angles, and the light yses to suggest that geometrical bands of light and
and shade both function by pyramids. The shade can actually be discerned, since the grada-
STUDIES OF THE GRADATIONS OF LIGHT angle c produces the first degree of brightness tions on a curved body are infinitely smooth, but
AND SHADOW ON AND BEHIND SPHERES because it is exposed to the window ab and to rather to illustrate the fundamental laws at work.
M.K.
c. 1492
pen and brown ink and wash, with traces of stylus,
on paper
l
each folio 24 x 38 (y/2 x 15)
inscribed with notes on light and shade
references: Richter 1970/1977, 148-149, 275;
Kemp 1989, 296-297; London 1989, 91
Bibliotheque de I'lnstitut de France, Paris

This manuscript originally comprised folios
81—114 of MS A in the Institut de France, but was
illegally removed and sold by Count Guglielmo
Libri in the 18305 and later returned. MS A can be
dated with reasonable certainty to circa 1492, and
the reproduced folios are of this date. The dia-
grams and notes were transcribed in folios 213 and
214 of the Codex Urbinas (the so-called Treatise
on Painting'), which was compiled after Leo-
nardo's death by his pupil, Francesco Melzi. The
circles visible in the margins are marks made by
the transcriber.
The meticulous study of the geometrical rules
governing the gradations of light and shade on
surfaces and of cast shadows and reflections occu-
pied a good deal of Leonardo's time in the early
14905. Comparable sets of analyses occur in MS c
(Institut de France), two folios of which are dated
1490 and 1493. Leonardo designed such studies
to give the painter access to precise rules for the
depiction of light and shade (not unlike the

280 CIRCA 1492