Grade 11 Art

Robert Land Academy 11 Art – December Stand-down Homework Capt. Aoki Mandatory Assignment: 1) Read the article “Perspective” Answer worksheet questions. 1 AVI3M Grade 11 Art Capt Aoki Worksheet for article “Perspective” 1) What is the definition of perspective in the graphic arts? 2) What are two characteristic features of perspective? 3) What is the basic concept of perspective? 4) Name 3 concepts that are commonly associated with perspective. 2 5) What is foreshortening? 6) What is a horizon line? 7) What is a vanishing point? 8) What assumption does a perspective drawing make of the viewing distance from the drawing? 9) Before perspective, how did paintings and drawings size objects? 10) Who defined the optical basis of perspective? 11) When was the optical basis of perspective defined? 3 12) Who demonstrated the geometrical method of perspective? 13) When was the geometrical method of perspective demonstrated? 14) According to Vasari, what was Brunelleschi’s demonstration of perspective? 15) What method was used extensively during the Quattrocento to show perspective in paintings and sculpture? 16) Who first published a treatise on the proper methods of perspective? 17) What was Alberti’s primary breakthrough concerning perspective? 4 18) Why did Leonardo da Vinci distrust Brunelleschi’s formulation of perspective? 19) What type of image has zero-point perspective? 5 Perspective A cube in two-point perspective. Rays of light travel from the object, through the picture plane, and to the viewer's eye. This is the basis for graphical perspective. Perspective (from Latin perspicere, to see clearly) in the graphic arts, such as drawing, is an approximate representation, on a flat surface (such as paper), of an image as it is perceived by the eye. The two most characteristic features of perspective are: . Objects are drawn smaller as their distance from the observer increases . The distortion of items when viewed at an angle (spatial foreshortening) In art, the term "foreshortening" is often used synonymously with perspective, even though foreshortening can occur in other types of non-perspective drawing representations (such as oblique parallel projection). 6 Basic concept Perspective works by representing the light that passes from a scene, through an imaginary rectangle (the painting), to the viewer's eye. It is similar to a viewer looking through a window and painting what is seen directly onto the windowpane. If viewed from the same spot as the windowpane was painted, the painted image would be identical to what was seen through the unpainted window. Each painted object in the scene is a flat, scaled down version of the object on the other side of the window. Because each portion of the painted object lies on the straight line from the viewer's eye to the equivalent portion of the real object it represents, the viewer cannot perceive (sans depth perception) any difference between the painted scene on the windowpane and the view of the real scene. Related concepts Some concepts that are commonly associated with perspectives include: . foreshortening . horizon line . vanishing points All perspective drawings assume a viewer is a certain distance away from the drawing. Objects are scaled relative to that viewer. Additionally, an object is often not scaled evenly: a circle often appears as an ellipse and a square can appear as a trapezoid. This distortion is referred to as foreshortening. Perspective drawings typically have an (often implied) horizon line. This line, directly opposite the viewer's eye, represents objects infinitely far away. They have shrunk, in the distance, to the infinitesimal thickness of a line. It is analogous to (and named after) the Earth's horizon. Any perspective representation of a scene that includes parallel lines has one or more vanishing points in a perspective drawing. A one-point perspective drawing means that the drawing has a single vanishing point, usually (though not necessarily) directly opposite the viewer's eye and usually (though not necessarily) on the horizon line. All lines parallel with the viewer's line of sight recede to the horizon towards this vanishing point. This is the standard "receding railroad tracks" phenomenon. A two-point drawing would have lines parallel to two different angles. Any number of vanishing points are possible in a drawing, one for each set of parallel lines that are at an angle relative to the plane of the drawing. Perspectives consisting of many parallel lines are observed most often when drawing architecture (architecture frequently uses lines parallel to the x, y, and z axes). Because it 7 is rare to have a scene consisting solely of lines parallel to the three Cartesian axes (x, y, and z), it is rare to see perspectives in practice with only one, two, or three vanishing points; Even a simple house frequently has a peaked roof which results in a minimum of five sets of parallel lines, in turn corresponding to up to five vanishing points. In contrast, natural scenes often do not have any sets of parallel lines. Such a perspective would thus have no vanishing points. History of perspective Early history Evolution of Perspective Before perspective, paintings and drawings typically sized objects and characters according to their spiritual or thematic importance, not with distance. Especially in Medieval art, art was meant to be read as a group of symbols, rather than seen as a coherent picture. The only method to show distance was by overlapping characters. Overlapping alone made poor drawings of architecture; medieval paintings of cities are a hodgepodge of lines in every direction. With the exception of dice, heraldry typically ignores perspective in the treatment of charges, though sometimes in later centuries charges are specified as in perspective. Illustration from the Old French translation of Guillaume de Tyr's Histoire d'Outremer, approx 1200-1300 AD. The lines on either side of the temple should, when continued, meet at the same point. They do not. 8 The optical basis of perspective was defined in the year 1000, when the Persian mathematician and philosopher Alhazen, in his Perspectiva, first explained that light projects conically into the eye. This was, theoretically, enough to translate objects convincingly onto a painting, but Alhalzen was concerned only with optics, not with painting. Conical translations are mathematically difficult, so a drawing constructed using them would be incredibly time consuming. The artist Giotto di Bondone first attempted drawings in perspective using an algebraic method to determine the placement of distant lines. The problem with using a linear ratio in this manner is that the apparent distance between a series of evenly spaced lines actually falls off with a sine dependence. To determine the ratio for each succeeding line, a recursive ratio must be used. This was not discovered until the 20th Century, in part by Erwin Panofsky. One of Giotto's first uses of his algebraic method of perspective was Jesus Before the Caïf. Although the picture does not conform to the modern, geometrical method of perspective, it does give a decent illusion of depth, and was a large step forward in Western art. Mathematical basis for perspective One hundred years later, in the early 1400s, Filippo Brunelleschi demonstrated the geometrical method of perspective, used today by artists, by painting the outlines of various Florentine buildings onto a mirror. When the building's outline was continued, he noticed that all of the lines converged on the horizon line. According to Vasari, he then set up a demonstration of his painting of the Baptistry in the incomplete doorway of the Duomo. He had the viewer look through a small hole on the back of the painting, facing the Baptistry. He would then set up a mirror, facing the viewer, which reflected his painting. To the viewer, the painting of the Baptistry and the Baptistry itself were nearly indistinguishable. Soon after, nearly every artist in Florence used geometrical perspective in their paintings, notably Donatello, who started sculpting elaborate checkerboard floors into the simple manger portrayed in the birth of Christ. Although hardly historically accurate, these checkerboard floors obeyed the primary laws of geometrical perspective: all lines converged to a vanishing point, and the rate at which the horizontal lines receded into the distance was graphically determined. This became an integral part of Quattrocento art. Not only was perspective a way of showing depth, it was also a new method of composing a painting. Paintings began to show a single, unified scene, rather than a combination of several. As shown by the quick proliferation of accurate perspective paintings in Florence, Brunelleschi likely understood (with help from his friend the mathematician Toscanelli), but did not publish, the mathematics behind perspective. Decades later, his friend Leon Battista Alberti wrote Della Pittura, a treatise on proper methods of showing distance in painting. Alberti's primary breakthrough was not to show the mathematics in terms of conical projections, as it actually appears to the eye. Instead, he formulated the theory 9 based on planar projections, or how the rays of light, passing from the viewer's eye to the landscape, would strike the picture plane (the painting). He was then able to calculate the apparent height of a distant object using two similar triangles. The mathematics behind congruent triangles is relatively simple, having been long ago formulated by Euclid. In viewing a wall, for instance, the first triangle has a vertex at the user's eye, and vertices at the top and bottom of the wall. The bottom of this triangle is the distance from the viewer to the wall. The second, similar triangle, has a point at the viewer's eye, and has a length equal to the viewer's eye from the painting. The height of the second triangle can then be determined through a simple ratio, as proven by Euclid.

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