# Foreshortening - An Illusion of Depth

Foreshortening - The Concept Foreshortening is an art technique to create an illusion of 3-dimensional space in a picture plane.
The basic principle is to use retrenching lines to draw an object as retreating into the background.
The image is distorted to add depth to the painting by making the closer portion of the subject brighter and bigger than the parts away from the observer.
It has evolved from the ancient technique of overlapping objects to create spatial illusion.
It is one of the many visual perspective styles, which the artists use to add realism to a painting.
The History Arab mathematician Alhazen (965-1039) first established the optical basis of perspective in his book 'Perspectiva' (1000).
In art, Giotto di Bondone (Italy, 1267-1337) used Alhazen's principles for the first time in his painting 'Jesus before the Caif.
' Renowned Italian Renaissance (1400-1525) architect Filippo Brunelleschi (1377-1446) popularized foreshortening.
His earliest artworks in this genre were the paintings of Florentine Baptistery and Palazzo Vechhio (the town hall of Florence, Italy).
Soon his contemporary Leon Battista Alberti (1404-72) formulated the laws of basic geometry in his book 'Della pittura' (On Painting) (1435).
Through this book, the principles of linear perspective became mathematically coherent.
It led to the widespread use of foreshortening in the art world.
Many Renaissance painters and architects dedicated themselves to the study of light and optical illusion to recreate realistic space in drawings and paintings.
The Types oPerspective Foreshortening: Linear and non-linear projection techniques form the basis of perspective foreshortening.
It uses the simple Euclidean geometry fundamental where objects closer to the viewer appear bigger than the distant ones.
While the linear extension assumes a constant ratio for this distortion, the non-linear one reduces the size in varying degree.
oNon-perspective Foreshortening: Oblique and orthogonal parallel projection techniques are the building blocks of this category.
In its simplest form, an object is extended on a plane by intersecting parallel rays from the object.
Coinciding projector and projection plane at an oblique or perpendicular angle to create 'forced depth' on the picture place, achieve it.
The aforementioned styles are also used for projection on cylindrical and spherical surfaces to generate more realistic distortion than the ones on flat surfaces.
The Artist and the Artworks o'Holy Trinity' (1428) by Masaccio (Italy, 1401-28) o'Battle of San Romano' (1432) by Paolo Uccello (Italy, 1397-1475) o'The Flagellation of Christ' (1460) by Piero della Francesca (Italy, 1415-92) o'Christ Giving the Keys to St.
Peter' (1482) by Pietro Perugino (Italy, 1446-1524) o'Dead Christ' (1480) by Andrea Mantegna (Italy, 1431-1506)