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Agrégation 2001 : image analysis

Responsable : Professeur Marie-Madeleine Martinet

 
POSITIVE AND NEGATIVE SHAPES
 

Positive shapes are the solid volumes (eg. buildings and objects), whereas negative shapes are the empty spaces between them (eg. streets, or patches of sky). Though our conscious attention focuses on the positive shapes so as to identify objects, the outlines of the areas between them form ‘negative shapes’ which have strong unconscious emotional appeal. This has been recognised in the psychology of visual perception, for instance recently by Betty Edwards.

In architecture, Bruno Zevi (an architectural theorist of the mid twentieth century) says the test of connoisseurs is that they will not only be able to define the shapes of the buildings, but also of the streets and squares between them: who is able to tell the shape of the Piazza di Spagna in Rome? (though everyone could describe the buildings surrounding it) Answer

 
Positive shapes Negative shapes
The attention focuses on the buildings, the pavement and the shadows The attention focuses on the blue vase-like shape of the sky between the buildings
 

This choice concerns the vertical representation:

 
Convergence of building lines Convergence of street walls
if the focus is on buildings, the principle of vertical convergence will be applied to them if it is on the street, the gaps will be emphasised
 
For a corner building:
 
conventional representation would be: But a painter may select:
If cityscapes (pictorial or photographic) are used as documents on the social history of urban environments, it is important to notice which of the two projections was used:
the artist throws into relief the buildings as the dominant feature of the view the emphasis is on the public space of the street (which is itself an issue in the social interpretation of city life)
 
http://www.tate.org.uk
Paul Nash, Mansions of the Dead (1932)

How are we to interpret the lines diverging towards the top?

 
Realistic interpretation:

The lines are really converging

Intellectual interpretation:

The lines are parallel, the observer is placed near the top of the view, which gives a vertical perspective illusion (high angle view)

Emotional interpretation:

the empty spaces are the dominant subject (death) and they are drawn correctly; the solid objects, which play a supporting part only, exist as foils to the void

The eye will naturally attempt to interpret the divergence of the solid volumes according to the usual geometry, and failure to identify such a pattern will cause a feeling of uncertainty which is sought for by the artist to release the emotions; simultaneously, the emotions will immediately be attracted to the negative shapes instead.
 
 
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Dernière mise à jour : 27/01/2004
 
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AGREGATION 2001
Image analysis
Landscape & Hypermedia
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