Danti’s book on the two rules of perspective of Vignola deals with a fundamental theme of architecture. Therefore, the book does not deal with a specific topic, but teaches basic knowledge that every architect needs. That is why the book itself is very focused on one concept, namely perspective. Danti conveys the subject of perspective by using comparisons. I have therefore decided to use comparison as a concept.
Already the title suggests that two rules for perspective drawing are explained in the book. These are actually methods and instructions from Vignola which Danti transmits to us. The two of them compare the two rules while providing basic knowledge in the field of vision and perspective drawing.
The two rules are called “costruzione legittima” and the distance-point method.
Kitao (1962) quotes Vignola’s position on his two rules: «The first “regola” is, in Vignola’s own words, “better known, easier to learn, but more awkward”; the second, on the other hand, is more abstract in both principle and procedure, hence “more difficult to grasp, but simpler to execute”. The two methods, the author believes, are nevertheless equally valid, for “they achieve one and the same end”».
In my opinion, this passage shows very well the intention which Danti pursues with his treatise on the two rules of Vignola. The goal was to create a standard work for perspective drawing. The reader is introduced to the subject step by step.
Danti explains how the human eye works and images are projected. Furthermore, he explains the two methods and at the same time presents a selection of tools for the draftsmen (Bartolini Bussi, 2012). It is therefore a catalog that shows the reader possibilities and brings him up to date.
To clarify, I’ll give a couple of examples of how Vignola works with comparisons. The same approach is used by Danti in his comments and explanations.
To explain the geometry behind light rays and perspective, Vignola supplements his explanations with physical drawings. He shows how the angles change when the distance to the object is increased or decreased.
The drawing tools are compared by the use of illustrations. However, one finds not only purely theoretical drawings, but also representations of people working with different kind of tools.
In the back of the book, examples of perspective drawings are shown. I guess this is an attempt to convince the reader of the two rules and to show what they are capable of (spiral staircase, capital, column, arches).
Kitao, T. (1962). ‘Prejudice in Perspective: A Study of Vignola’s Perspective Treatise’. The Art Bulletin, vol. 44, no. 3: 173-194.
Bussi, M. (2012). ‘The perspectograph’. For the Learning of Mathematics, vol. 32, no. 2: 34-34.