Comment on “Art History and the Criticism of Computer-Generated Images”

C()M~lEN'L\RIES Readers'comments offeringsubstantialtheoretical and practical contributions to issuesthat have beenraised in textspublished in Leonardo are welcomed. The editorsreservethe right to edit and shortenletters. Lettersshould be written in Englishand sentto the Main Editorial Office. COMMENT ON "ART HISTORY AND THE CRITICISM OF COMPUTERGENERATED IMAGES" I read an interesting article byJames Elkins, "Art History and the Criticism of Computer-Generated Images," in the Theoretical Perspectives section of Leonardo 27, No.4, 335-342, 1994. However, the author is mistaken when he makes reference to Renaissance perspective and claims that "In addition, Alberti's construction does not include a horizon line, and horizon lines appear only intermittently in contemporaneous accounts." This statement cannot be overlooked because it may lead the reader to accept a mistaken appreciation . Alberti defines not only the horizon line, but also the elements necessary to describe the model of his method. He cal1s the horizon line linea centrica [l] precisely because it passes through the punto centrico-in other words, through the point of the line of sight that vanishes at infinity [2]. Alberti cal1ed this line of sight raggio centrico [3]. In my opinion, Alberti's La Pittvra represents the synthesis of Renaissance perspective theory as tested by Brunel1eschi in the piazza of San Giovanni and the piazza del1a Signoria, executed by Masaccio in La Trinitd and cast in bronze in the works of Donatel1o and Ghiberti. Another characteristic of the work is that it uses the terms consistently [4], defining each one as the description of the concepts develops, so that there is no doubt as to the interpretation of his procedure. Another debatable point arises when Elkins states: "Alberti's construction did not produce grid lines very far into the distance.... It is difficult to continue transversals into deep distance using Alberti's method." Alberti makes an elegant presentation of his concept of infinite depth when he describes his procedure [5], making clear that when the visual rays are directed towards the punto centrico, they arrive at the theoretical point of infinity and, therefore, the transversal intervals become shorter and shorter until they join together. In another passage, Alberti compares his method of a pyramid of visuals to a cage [5]-that is to say, he not only considers the broadening of the pavement , but also imagines a spatial model in which the visual rays cover the entire superficie (picture plane). In an essay that is soon to be published, I shal1 present my interpretation ofAlberti's method. ToMAs GARCiA SALGADO Researcher, Faculty of Architecture Universidad Nacional Autonoma de Mexico Palacio de Versalles 200 Lomas Reforma c.p. 11020 Mexico D.F. References 1. "... Tiro di sopra un'altra linea transversa egualmente lontana da l'altre piu basse, laquale tagli duo lati, che stanno fermi del gran cuadrato, e habbia a passare per 10punto centrico. Questa linea rrr'e un termine, e confine, ilquale nessuna quantita non piu alta, che l'occhio dichi guarda, possa passare. Et questa perche ella passa per 10 punta centrieo, per ciasi chiama centrica." Leonbattista Alberti, La PiU1Ira (tradotta per M. Lodovieo Domenichi, in Vinegia Appresso Gabriel, Giolito de Ferrari (1547) p. 17. 2. In the Modular Network Perspective model, the line of sight becomes the "Symmetrical Sight Line." Tomas Garda Salgado, Leonardo21, No.3, 277-284 (1988). 3. Raggio centrico chiamiamo quello, ilqual solo ferisce la quantita di modo, che gli anguli eguali d'ogni parte, rispondano a gli anguli, che si gli accostano ... di maniera, che meritamente si puo chiamare capitano, e principe de i raggi." Alberti [1] p. 9. 4. "Lontananza, lunghezza, larghezza, spaZla, finestra, punta centrico, perpendiculare, distantia, distanza, superficie, superficie piana, superficie spheriea, raggio centrico, raggi estremi, raggi di mezzo, linea centrica, linea diritta, linea bassa, linea traversa, quadrangulo, ad infinita, diametro, paralello, misura, prospettiva, lembo, anguli, l'occhio, la vista, dipingere." Alberti [1]. 5. "Fatto il punto centrico, tiro le linee dritte dal medesimo punta centrieo a le divisioni d'una in una de la linea, che sta a giacere; lequali linee mi dimostrano, in che modo quasi ad infinita lontananza Ie quantita di traverso per suecedere a 10 intervallo si ristringano sotto la vista." Alberti [1] p. 15-16...