Alberti SKETCHLAB NOTES 5 PERSPECTIVE PRECISION AND PROPORTION FOR MR RONNIE TURNBULL 1
BEFORE THE RENAISSANCE PERSPECTIVE DRAWING IS The art of drawing solid objects on a two-dimensional surface so as to give the right impression of their height, width, depth, and position in relation to each other when viewed from a particular point. Examples of early attempts to convey perspective 2
BRUNELLECHI S BREAKTHROUGH Before artists began to understand the geometry behind the illusion of perspective they tried many different devices for implying distance. These includes reducing the size of distant objects using angles and stacking things heirarchically. In the 15 th century however the architect Brunelleschi made a discovery which revolutionised art and the way we see and represent the word. This is plagarised from the internet: An introduction to Filippo Brunelleschi's experiment regarding linear perspective, c. 1420, in front of the Baptistry in Florence http://www.artbabble.org/video/ngadc/empire-eye-magic-illusion-trinity- masaccio-part-2 http://www.artbabble.org/topic/series/empire-eye-magic-illusion http://smarthistory.khanacademy.org/brunelleschi.html Brunelleschi and the Rediscovery of Linear Perspective Before looking at painting in the Early Renaissance, we need to learn about the discovery or rediscovery of linear perspective sometime close to 1420 by Filippo Brunelleschi (rediscovery, because the ancient Greeks and Romans may have understood linear perspective too, but if so, knowledge of it was lost during the Middle Ages). Linear perspective is a way of creating a convincing, perfect illusion of space on a flat or two- 3
HEADING dimensional surface. Nearly every Renaissance artist wanted linear perspective a way of creating an accurate illusion of space that could match the new naturalism then being applied to human figure. http://www.math.sunysb.edu/~tony/whatsnew/column/ alberti-0102/java/piero2.htm When Brunelleschi (re)discovered linear prespective circa 1420, Florentine painters and sculptors became obsessed with it, especially after detailed instructions were published in a painting manual written by a fellow Florentine, Leon Battista Alberti, in 1435. John Berger, an art historian, notes that the convention of perspective fits within Renaissance Humanism because "it structured all images of reality to address a single spectator who, unlike God, could only be in one place at a time." In other words, linear perspective eliminates the multiple viewpoints that we see in medieval art, and creates an illusion of space from a single, fixed viewpoint. This suggests a renewed focus on the individual viewer, and we know that individualism is an important part of the Humanism of the Renaissance. Diagram of the main elements of linear perspective horizon line, vanishing point, and orthogonals. 4
EXAMPLES OF EARLY PERSPECTIVE Giotto Giotto very nearly got it but used perspective in ione dimension only. Massachio however a few years later mastered the art of constructing the illusion of depth based on geometry Massachio 5
HEADING Early Applications of Linear Perspective Representing the Body What renaissance artists had clearly achieved through the careful observation of nature, including studies of anatomical dissections, was the means to recreate the 3-dimensional physical reality of the human form on 2-dimensional surfaces. In part, the key to this achievement lay in understanding the underlying, hidden structure of the human body which then enabled the artist to produce realistic representations of what he saw on the flat surface of a wall (in the case of frescoes) or on a wooden panel or paper (in the case of drawings). Artists in the early 15th century had learned to portray the human form with faithful accuracy through careful observation and anatomical dissection, and in 1420 Brunelleschi's experiment provided a correspondingly accurate representation of physical space. Antonio Manetti, Brunelleschi's biographer, writing a century later, describes the experiment based on careful mathematical calculation. Perspective and Architecture It seems reasonable that Brunelleschi devised the method of perspective for architectural purposes he is said by Manetti to have made a ground plan for the Church of Santo Spirito in Florence (1434-82) on the basis of which he produced a perspective drawing to show his clients how it would look after it 6
HEADING was built. We can compare this drawing with a modern photo of the actual church. This video clip allows you to crossfade back and forth between the original perspective drawing and the modern photograph. It is clear how effective the new technique of mathematical perspective was in depicting spatial reality. Masaccio, Holy Trinity, 1427, fresco (Santa Maria Novella, Florence) The Body in Space But this was just the beginning. Ten years later, the painter Masaccio applied the new method of mathematical perspective even more spectacularly in the fresco The Holy Trinity, where the barrel vaulted ceiling is incredible in its complex, mathematical use of perspective. Here lines overlay Masaccio's actual geometric framework to make clear the structure of the perspective itself. From the geometry it is actually possible to work backwards to accurately measure and reconstruct the full 3-dimensional space that Masaccio depicts, illustrating exactly, Brunelleschi's interest in being able to translate schemata directly between two and three-dimensional spaces. It was not long before a decisive step was taken by Leon Battista Alberti, who published a treatise on perspective, Della Pitture (or On Painting), in 1435. Once Alberti's treatise was published, knowledge of perspective no longer had to be passed on by word of mouth. For some it became a matter of consuming artistic, even philosophical interest. Text by Dr. Joseph Dauben 7
HOW DO WE DO IT? Draw a light horizontal line as a guide to the horizon at your eye level Unless the faces of buildings are co-planar they will have different vanishing points. Using a viewfinder establish a cone of vision not more that 60 degrees Look to see where line appear to converge in the distance. Where they intersect with your horizon you have your vanishing points. Many of these will be off your paper. Note the ones that are on your paper. Add a few vertical lines to denote the edges of buildings. Use the edge of your paper to steady your hand. 8
OBJECTS: ALIGNING TO A VANISHING POINT Any objects/buildings with faces which are parellel ( on the same plane) will have horizontals which converge at the same VP. All lines on the same plane to any face will converge at the same VP. http://www.youtube.com/watch?v=aw42zyqj1si http://www.youtube.com/watch?v=2gpqmxchoeu 9
DIVIDING FACADES Establish the outline of the building/objects you are drawing with just the minimum of lines Then draw a X shape from one corner to the other of your facade This establishes the mid point its clearly not the geometric centre 10
MEASURING DIVISIONS Then do the same again in each of the two halves-this subdivides your facade into four- you can usually do the rest by eye just keep the ratio between any adjacent area the same. This ratio changes as the angle of the wall or plane is more acute to the viewer. 11
LOOKING FOR RELATIONSHIP A viewfinder made of stiff card is very useful both for choosing a view to draw and for assessing angles. Best to make a couple with slightly different proportions and mark thirds along top and bottom. Put your focal point near one of the intersections of these thirds and the horizon line close to one of the vertical ones. Look for geometric shapes within your view. Especially squares. These are an invaluable aid to getting things in the right place on paper. See example below. 12
SKETCHLAB Week 5 PERSPECTIVE DRAWINGS Use a pencil or pen to help asses the angles of roofs, road etc Hold it up align it with the angle you want to denote then drop it down to your drawing. Its easy then to judge if something is badly out of alignment. Similarly use a horizontal or vertical pencil to check for alignment. Hockney And you can use use the length of the pencil to check relative lengths, holding it at arms length and sliding the thumb up and down as a gauge. 13
ELLIPSES T h e s e a re p o i n t s where ellipse is at a tangent to the square First draw a bounding square in perspective. Draw a cross shape and then a horizontal and vertical to find where the edges of the ellipse will be. The ellipse will always be tangential to the square at these points. Add some dots half way between the diamond shape and the corners of the square. The ellipse will pass through these too. The ellipse in perspective is far from symmetric. Note a common mistake its too flattened here 14
DISCOVERING GEOMETRY STRUCTURE AND PATTERN Most complex forms can be simplified to a combination of the following 15
AND DON T FORGET TO ENJOY IT Finally keep it all in: Proportion: How things fit together, big and small, nearby and distant. 16