Entasis

Korinthische Säulenordnung Entasis2

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Entasis refers to a slight curvature in the architectural design of columns, which was particularly prominent in the ancient Greek style. This subtle convex curve is introduced to counteract the optical illusion of concavity that can occur when viewing a perfectly straight column from a distance. The term itself is derived from the Greek word entasis, which means 'tension' or 'straining'. This architectural technique enhances the aesthetic appeal of buildings and structures, making columns appear more robust and dynamically engaged with their load. Entasis is most commonly associated with Doric and, to a lesser extent, Ionic orders of Greek architecture, although it can be found in various forms in other styles and periods as well.

History and Purpose

The use of entasis dates back to the early Classical period of Greek architecture, around the 5th century BCE. The most famous example of entasis can be seen in the Parthenon, on the Acropolis of Athens. Here, the columns exhibit a gentle swell, which is not immediately noticeable to the naked eye but gives the structure a sense of vitality and organic presence. The purpose of entasis went beyond mere aesthetics; it was also a sophisticated response to optical illusions. Ancient architects and builders recognized that when long, straight lines are viewed from a distance, they can appear to sag or dip in the middle. By introducing entasis, they corrected this visual distortion, ensuring that the columns appeared straight and in perfect harmony with the rest of the structure.

Technical Aspects

The technical execution of entasis involves a slight increase in the diameter of the column shaft from the bottom upwards, with the maximum bulge typically occurring at about one-third of the column's height. From this point, the column gently tapers to its top. The degree of curvature varies from one architectural work to another, with some columns having a more pronounced entasis than others. The precise calculation of the curve requires an understanding of geometry and optics, making entasis a testament to the advanced mathematical and engineering skills of ancient architects.

Impact on Architecture

Entasis has had a lasting impact on architecture, influencing not only ancient Greek and Roman builders but also modern architects who seek to incorporate classical elements into their designs. It is seen as a hallmark of classical beauty, embodying principles of symmetry, proportion, and balance. Moreover, entasis has been studied and admired as an example of how architecture can respond to and manipulate human perception to achieve a desired visual effect.

See Also

• Classical order
• Column
• Optical corrections in Greek architecture
• Vitruvius