Linear perspective - this is a mathematical system for projecting the three-dimensional world onto a two-dimensional surface, such as canvas or paper. Basically, this type of perspective begins with a horizon line, which defines the farthest distance of the background and has a central vanishing point. Diagonal lines called Orthogonals are drawn to this vanishing point, they can be drawn from the bottom of the picture plane, which then defines the foreground of the space. The orthogonals, vanishing point, and horizon line establish the space in which the artist may arrange figures, objects, or architecture as they appear to exist, and make them appear to be three dimensional.
Once these basic elements have been set in place, the artist can then add further elements to create a more complicated, yet more realistic, space. To represent a square-tiled floor, the artist would choose another point on the horizon line, called the distance point, and draws a line through the orthogonals to a point at the bottom of the picture plane. The points at which this line bisects the orthogonals establish the points at which the horizontal lines, called transversals, may be placed. These lines represent the correct perspective regression of the square tiles into the space.
Some artists of the Renaissance were not as concerned with putting their subjects in perfect perspective as they were with making religious statements. For example, in pictures that include the Virgin Mary the vanishing point is often intentionally placed on Mary's womb to indicate her place as the mother of Christ. This placement of the vanishing point has religious significance and may not be related to the intention to create a rational perspective space. Artists still use this method today if they wish to create a certain focal point that doesn’t necessarily flow into the horizon line as such. You have to be careful when using this type of perspective however because if you choose a short distance between the distance point and the vanishing point then the perspective will appear warped. The distance between the distance point and the vanishing point should, in theory, correspond exactly to the distance between the viewer’s eye and the picture plane. When the distance between the points is small, the viewer must place his or her eye at this same distance from the painting directly in front of the distance point in order to see the work with no distortion whatsoever. When the viewer stands back from the work, the space in the image will appear distorted.
What about Anamorphous forms? - this involves stretching an ordinary linear-perspective image in one or more directions to obscure its original form. To achieve this, the artist draws a grid over the original image and then translates the image point by point to a grid that has been stretched. If the viewer looks at the image directly, it appears formless and amorphous. In order to recognize the image, the eye of the viewer must be positioned from a particular spot, generally off to the side, and from this point the image appears in linear perspective. This is commonly used in illusion type work.
Curvilinear perspective is an alternate to linear perspective. Although technically all straight lines are curved, curvilinear lines are suppressed in Western painting—that is, straight lines are represented as straight rather than arced. In the 19th century, a group of artists made an attempt to return curvilinear perspective to painting, but the idea was short lived because it presented a philosophical problem. When observing lines in the real world, such those of as walls and buildings, the lines appear curved. (Think of standing in front of a long wall, and looking left and right: The top of the wall seems to curve up from either side.) So therefore a wall in a painting, drawn with straight lines, can also seem curved. and if those curves are represented in painting they will seem doubly curved. This tension between reality and the representation of reality in painting posed a challenge to the painters who employed this technique.
There are some elements of representation over which linear perspective has no power, such as landscapes, faces, and organic forms, for this type of perspective only describes linear things.
Since the Renaissance, painters have reworked and refined linear perspective. The American 19th-century realist Thomas Eakins who created remarkably accurate outdoor scenes, with shadows painted so precisely that art historians have been able to determine, based on their knowledge of where the works were painted, the exact date and time of day he painted them.
Picasso was one of the first to completely go against the grain and defy perspective, creating his own with cubism and altering perspective to suit his own style of art.
Computer Art – take a look at any computer game and you will see that that all figures and objects are drawn using a perfect geometric grid. Regardless of the vantage point from which the player views figures in a game, all figures, objects, and elements in the settings adhere to the established rules of representation. Perspective is both an exacting art and an exacting science, and it is still an important aspect of art as a rule.
Posted: Sunday 31 January 2010