A classical column is not a decorative ornament, nor is it an attractive stand-alone embellishment like an ornate bronze door handle. Rather, a classical column is part of an architectural order. (The five generally recognized orders are: Doric, Ionic, Corinthian, Tuscan, and Composite.) Although the column (and especially its capital) is the most readily recognized component of each order, it is merely a component. In fact, one can create a fully classical building without a single column in sight through the use of classical planning, proportions, and non-column elements.
The canonical orders are architectural systems, with a carefully refined set of relationships that have evolved over the centuries. Each architectural order is the result of careful deployment and arrangement of all the order’s components, from the largest column to the smallest molding, according to a range of generally accepted principles. Contrary to popular belief, there is no single set of formulas or ratios that can be automatically applied to each order. Instead, there is a range of proportions and relationships that can only be fully understood, and skillfully manipulated, after considerable study and practice.
Even though it is merely one of numerous components of an architectural order, the fact remains that the column is the most conspicuous element of each order; most people look to the column capital for quick identification of a classical order.
And, in truth, columns are the “stars” of the orders because of the way they stand out. (Some observers have called the Doric Order the most perfectly balanced order because the relatively modest Doric column doesn’t automatically focus all of the viewer’s attention on the column capital — as is frequently the case with the Ionic and Corinthian.) Because of their starring role, when a designer uses columns, it’s critical that (1) the column be architecturally correct; and (2) the column be set into an architecturally appropriate context.
An architecturally correct column is one that has the general modeling and proportions evolved over centuries of use in the Greco-Roman world. A true classical column is an anthropomorphic shape, often referred to as an analog of the human form, with a clearly defined head and foot: If you mount a Corinthian column upside down, the result looks absurd even to the most untrained observer. This need for specific vertical orientation is what differentiates the column from a post: A post can be turned end-for-end without anyone being the wiser.
A crucial part of the modeling of the classical column is its entasis, the subtle curvature that causes the column to swell at the bottom, as if to express the load that it is bearing. The lack of entasis on extruded aluminum “columns” is why they look so lifeless in place. Because of the extrusion technology used in their manufacture, extruded aluminum “columns” have a uniform diameter throughout their length. An extruded aluminum “column” is actually a post, because the shaft can be turned upside down and — without entasis — it will look exactly the same.
Without belaboring the point, it should be noted in passing that authors and designers since the Renaissance have been taking the anthropomorphic shapes of classical columns and assigning them “personalities.” The Doric and Tuscan shapes are often thought of as sturdy and muscular, and as such Doric columns are frequently assigned the “heavy lifting” job at the bottom level when orders are stacked, or when there is a visually heavy load to be borne. The Ionic column, being the slenderest of the classical columns, is thought to be the most feminine, with the sensuous curves of the Ionic volute being a highly stylized representation of flowing hair. The Corinthian column is seen as the most sophisticated and dignified of the orders, and thus is often found in major public buildings like banks and courthouses.