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ITALIANA - AIC Associazione Italiana Autori della Fotografia ...

ITALIANA - AIC Associazione Italiana Autori della Fotografia ...

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<strong>AIC</strong><br />

fece la prima tavoletta come la<br />

seconda?<br />

Perché fece ricorso per la<br />

comparazione alla riflessione<br />

nello specchio?<br />

Perché scelse come punto di<br />

vista <strong>della</strong> prima tavoletta un<br />

punto all'interno del Duomo.<br />

La possibilità del confronto<br />

consentì l'adozione del metodo<br />

dell'intersegazione come<br />

soluzione legittima del<br />

problema illusivo delle pitture<br />

che ritraevano il vero<br />

"... ma bene s'aspetti pittura<br />

quale paia molto rilevata e<br />

simigliata a chi ella ritrae<br />

qualcosa non intendo io sanza<br />

aiuto del velo alcuno mai<br />

possa".<br />

L.B. Alberti - De Pictura<br />

Quando invece il pittore<br />

costruiva non più fingendo<br />

quello che si vede ma a partire<br />

dalla propria fantasia<br />

"grandissima opera del pittore<br />

sarà l'Istoria"<br />

L.B. Alberti - De Pictura"<br />

il confronto non era più<br />

possibile.<br />

Come stabilire allora la<br />

legittimità <strong>della</strong> intersegazione?<br />

Il Brunelleschi deve avere urtato<br />

contro questa difficoltà e deve<br />

averla superata facendo ricorso<br />

al modello <strong>della</strong> visione descritto<br />

in tanti trattati di perspectiva<br />

medievali.<br />

L'occhio vi era chiamato anche<br />

camera obscura naturalis,<br />

mentre la camera obscura<br />

artificialis ne era il modello, e<br />

l'osservatore dentro la camera<br />

obscura artificiale la metafora<br />

... it was no longer possible to make a comparison.<br />

How could one then establish the validity of the intersection method?<br />

Brunelleschi must have encountered this problem, and found a solution<br />

to it by referring to the visual model described in many of the mediaeval<br />

treatises on perspective. Here, the eye was referred to as the camera<br />

obscura naturalis, while the model constituted the artificial camera<br />

obscura, and the observer inside the artificial camera obscura became<br />

the metaphor of the visual spirit in the eye which judges the likenesses<br />

that enter through the pupil.<br />

"... the process in which objects transmit their likeness, or their image in<br />

perspective, to the eye... can be demonstrated when the likenesses of the<br />

illuminated objects penetrate though a small round hole in a very dark<br />

room; then, allowing these likenesses to fall on a piece of white paper...<br />

fairly near the hole, you will see all the aforementioned ol>jects appear on<br />

the same piece of paper, but masaran minori, in other words, upside<br />

down..."<br />

Brunelleschi could have reasoned things out in the following manner: if<br />

it can be demonstrated that the painting executed by copying the image<br />

obtained in the artificial camera obscura appears like the real; then its<br />

being similar to that obtained with the intersection of the visual pyramid<br />

demonstrated that the latter appears like the real because it is similar to<br />

the image obtained by the intersection in the eye and, therefore, valid<br />

Cfig-5)<br />

"... now, I will tell you how to effect a very beautiful experiment<br />

concerning perspective. If you wish to observe how everything diminishes<br />

in Nature; not only as regards the outline of everything and every part,<br />

dello spirito visivo che<br />

nell'occhio giudica le similitudini<br />

che entrano attraverso la pupilla,<br />

"...lassperienza che mosstra<br />

liobbietti mandino loro spetie<br />

oversimilitudini intersegate<br />

dentro allocchio... si dimostra<br />

quando per alchuno picholo<br />

spiracolo rotondo penetreranno<br />

le spetie delli obbietti<br />

alluminati in abitazione forte<br />

osscura alora tu riceverai tali<br />

spetie nuna carta bianca...<br />

alquanto vicina a esso spiracholo<br />

e vedrai tutti li predetti obbietti<br />

in essa carta colle lor proprie<br />

figure masaran minori ossieno<br />

sottosopra".<br />

Il Brunelleschi può aver<br />

ragionato così: se si dimostra<br />

che la pittura costruita<br />

ricalcando l'immagine <strong>della</strong><br />

camera oscura artificiale, fa<br />

Fig. 5<br />

but also the colour, shadow and likeness, make a hole, the size of an<br />

eye-glass lens, in the shutter of a window, in the room from which you<br />

wish to look, and take a presbyopic lens... and fit it into the hole... then<br />

take a sheet of paper and hold it opposite the lens, far back enough so that<br />

you can just see the view outside over the top of it., thus, being able to see<br />

the outline of everything on the paper, you can trace all the perspective that<br />

appears there with a brush, shading and colouring it in the same delicate<br />

manner as Nature herself... " (fig. 3-6)<br />

Daniele Barbaro<br />

"La pratica <strong>della</strong> perspectiva" 1568<br />

Brunelleschi, Leonardo and Barbaro possessed the same<br />

optical-geometrical and technical knowledge, and the same techniques<br />

were available to all of them.<br />

It would therefore seem reasonable to suppose that Brunelleschi was able<br />

to:<br />

"... trace the perspective with a brush in the same manner as Nature<br />

herself... "<br />

This would explain the strange device of using a mirror to compare the<br />

first painting with the real Baptistry (fig. 1 ): the painting, which had<br />

been effected "...upside down.. ", would have had to have been rotated 18CP<br />

about its vertical axis to compare it with the real, and then seen reflected<br />

in a mirror from behind, just like a daguerrotype, which is, in fact, a<br />

positive painting created in a camera obscura<br />

The daguerrotype, like Brunelleschi's first painting, has to be turned<br />

upside down, and then turned towards the observer, if it is to be viewed

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