Agrégation 2001 : image analysis

Agrégation 2000

Images of New York: methods of picture analysis
Can you crack the visual codes of pictures?

Professeur Marie-Madeleine MARTINET

Photograph taken with a 40 mm lens   

 

keys
for a present-day Gold Bug

 

The theory will be found in Villes en visite virtuelle

Finding the answers requires raising the right questions first, and here are five of them:

Elevation or perspective?
Frontal or oblique view?
Where is the vanishing point?
How are the distances articulated?
How does the composition relate perpendiculars to diagonals?

 

ELEVATION OR PERSPECTIVE?

Elevation

Perspective

Option The draughtsman may select to draw a building with the lines of the wall remaining vertical as they are in reality; such views are made of rectangles. 

Interpretation This is the practice in architectural draughtsmanship, and choosing it will make the drawing look professional and technical, like an engineering diagram.

Option The draughtsman may also select to show the verticals strongly converging towards the top, as when a passer-by looks up towards the top of a tall building from its foot ; the volumes approximate conic shapes.

Interpretation This is the practice in landscape and townscape painting, and it will make the picture look like ‘’an artist’s impression.’’

The choice is obviously important in cities whose image relies on a skyline of skyscrapers (though only a small proportion of its buildings are actually skyscrapers).

Historical significance:

Around 1930 (when the major skyscrapers such as the Chrysler and the Empire State Building were competing for the title of ‘’tallest building in the world ‘’), numerous artists selected to give views of them as close as possible to the elevation, with parallel lines placing these examples of extreme modernity in the timeless classical tradition of architectural draughtsmanship.

The perspective presentation on the contrary is more frequent in recent views.

It is possible in photography either

(a lens of more than 50 mm of focal length)

When analyzing a photograph, it is necessary to guess the focal distance of the lens which was probably employed so as to understand the artist’s intention.

Examples

Elevation

Perspective

http://www.esbnyc.com http://www.realtech.com/webcam
The home page of the Empire State Building website shows the hall of the building with its 1930s decorative panel in the centre representing the skyscraper in elevation: this is period aesthetics (Art Deco).

On both sides, the walls of the hall are in perspective (projected as oblique lines); so the view of the past in the distance is framed in a present-day mode of vision. Entering the website is boarding a visual time-machine.

This site shows views of Manhattan from the top of a skyscraper in different directions and at several times of the day. Since it emphasizes the multiple appearances a cityscape takes according to circumstances – and the technology’s capacity to evoke them – it also marks the transformed shape of the buildings due to the perspective illusion caused by the high viewpoint: verticals become oblique lines converging towards the ground.

Historical significance
In the past, low horizons were used to denote the superiority of the sitter. In New York townscape photography, high-rise buildings were, in the first decades of skyscraper architecture, frequently seen at half-height, avoiding extremes of towering or plunging effects. When they occur, they are thus striking.
In photography and film, plunging effects can be obtained by ‘’high angle views’’ whereas towering objects are usually viewed with a ‘’low-angle.’’

Examples
Horizon line at low level
High horizon-line
http://www.nypl.org
http://www.nypl.org
Berenice Abbott’s photograph of ‘’Department of Docks and Police Station, May 5, 1936’’ gives a view of a low-rise at street level. The horizon line (indicating the height of the observer’s eyes) is also at the level of the eyes of characters in the foreground; so the viewers share the station point of the man-in-the-street.
In the same site, the section on Lewis Wickes Hines’s ‘’the Construction of the Empire State Building, 1930-31’’ shows ‘’a worker at the edge of a platform, looking North’’ from a high vantage point in the scaffoldings, making us share the dangerous station of the workmen.

HOW ARE THE DISTANCES ARTICULATED?
Foreground
Background


Option Among the ‘’three distances’’ which traditionally structure the landscape so as to give it depth, the painter may select to emphasize the foreground, using the middle distance as a transition towards a distance which serves as a mere ‘’background’’ to enhance the foreground motifs.
Interpretation This is the case in heroic portraiture or classical landscape, where ‘’foreground’’ signifies ‘’importance’’ and ‘’background’’ supposes ‘’insignificance.’’
Option The painter may prefer to focus on the distance, using the foreground and middle distance as foils to lead the eye towards the central motifs placed behind them.
Interpretation This structure implies that the setting as a whole is important.

Historical significance

The celebrity of Manhattan’s ‘’skyline’’ implies a reversal of European conventions giving pre-eminence to the foreground (a hierarchy still existent in the language), and an assertion that the city as a whole is the focus of attention.

Examples

Foreground

Background

http://www.worldstallest.com http://www.theinsider.com/NYC
This site focuses on some buildings, and shows close-ups of them. This site gives a view of the whole of New York, and its logo reproduces the famous skyline.

 

 

HOW DOES THE COMPOSITION RELATE PERPENDICULARS TO DIAGONALS?

Square framing

Diagonals

Option In a rectangular composition, the draughtsman may select to place main compositional elements on the square built within the rectangle on the smaller side of the rectangle (in red). For the longer side of the rectangle, it is its half that will form the side of the construction squares (in green).

Interpretation The key elements can be found by tracing this compositional grid which points to them.

Option The draughtsman may choose to place the main lines of the construction on diagonals.

Interpretation Like the oblique view (to which it can be associated), this composition emphasizes dynamism.

 

Historical significance

Selecting these time-honoured methods stresses the rigorous construction of modern townscapes. It is often a way of indicating, in addition to objects, the articulation between the major elements or distances, stressing the framing effects.

Examples

Square framing

Diagonals

http://www.whitney.org http://www.nypl.org
In the site of the virtual exhibition ‘’The American Century’’ (accompanying the current exhibition at the Whitney Museum), the timeline allows the user to select (for 1931) Earle Horter’s The Chrysler Building Under Construction. The square within the rectangle falls at the level of the cornice of the foreground building, emphasizing this separation between the foreground and the Chrysler. The squares formed on the half-height create a vertical on the dark band which underlines the Chrysler to the left. In both cases, it is the framing element which is highlighted. Lewis Wickes Hines’s ‘’A worker hanging on to two steel beams’’ shows the man against a gridiron pattern of streets placed diagonally; this emphasizes the oblique gesture of his arm and his unbalanced position.