Via Lucis is a photography blog but we also do a lot of writing. We are not trying to preach, but to provide context for our photography of the Romanesque and Gothic churches. PJ’s take is “I’m trying to capture the architecture, the play of light on stone, and the beauty of the church. I try to find a way to express the spirit of the church. Sometimes I’m just moved by the shapes and the patterns.”
For myself, I’m trying to understand those forces that moved the people who built the churches and to explore the genius of the builders. This post is another examination of that genius. In this case, we are talking about using imperfections to give the appearance of perfection.
Entasis was primarily used on massive structures (like the Parthenon) that are meant to be viewed from rather large distances and corrects for parallax distortion. As the distance increases, a phenomenon occurs that makes parallel lines (such as the sides of columns) appear to narrow in the middle.
The phenomenon of entasis is well known and documented. The Parthenon is famous for it. I still remember my first realization that the Greeks distorted the perfection of their columns so that they would appear to be perfect – to me this was the very definition of genius. But the Greeks did not invent this concept – like their mathematics, they borrowed it from the Egyptians. From the Egyptians even more than the Greeks we understand that entasis was less corrective of an optical distortion than an aesthetic correction.
In Egypt, these visual compensations were used a thousand years before the Parthenon – the statue of Ramses at Luxor has an example of a compensation with the exaggerated smile of Ramses.
Christopher Dunn points out in his Lost Technologies of Ancient Egypt: Advanced Engineering in the Temples of the Pharaohs that only the mouth is smiling; the rest of the face is at rest. But he identifies the reason for this exaggeration – the smile only appears exaggerated when we view the head from the the same elevation. When viewed from the ground level far below, the smile is more natural. Without the exaggeration, the mouth would appear to scowl.
Less well known is that entasis and these visual distortions were used by medieval builders in their churches and cathedrals. For years it was mistakenly believed that these imperfections existed because the builders thought that only God was perfect and so the church could not be so. This misunderstanding carried over into modern times. The builders of Washington National Cathedral added several “imperfections” for this very reason.
There are other fanciful notions to explain medieval construction anomalies. There is a well-known phenomenon in medieval churches that the apse is often slightly off-center to the line of the nave.
The romantic notion was that this reflected the passion of Christ, whose head fell to one side during the crucifixion. In reality, it seems to be a form of entasis. By adjusting the sight line to the columns of the hemicycle, we see the spaces more clearly and the columns don’t seem to run together.
The more realistic understanding of medieval distortions was propounded in the United States by William Henry Goodyear in a series of influential lectures in 1915. He proposed that the irregularities and asymmetries in medieval buildings were not errors but were carefully planned in the structures.
“The extreme subtlety and extraordinary constructive skill and forethought that are found in these arrangements, when considered with their inconspicuous and generally unobtrusive character, justify us in applying the term ‘architectural refinements’ to them.” William Henry Goodyear, Illustrated Catalog of Photographs and Surveys of Architectural Refinements in Medieval Buildings
These photographs from Goodyear’s Illustrated Catalogue Of Photographs & Surveys Of Architectural Refinements In Medieval Buildings (Edinburgh 1905) illustrate some of the remarkable refinements created by medieval builders.
In the Cathédrale Notre Dame d’Amiens, the soaring nave features a spreading of the nave columns outward to compensate for the vertical perspective convergence when seen from below. Notice how the upper portions of the nave columns actually start to lean outwards. “The measures establish the fact that the inclinations are practically uniform throughout the nave and choir, although the wall measures average a little less than those of the piers … The constructive strain is entirely carried by the piers, and their leans are the ones to be considered, especially as the entire inclinations, from pavement to vaulting, are related to these measures for the piers.”
Goodyear also states, “It appears probable that the diverging piers at the crossing of Notre-Dame [de Paris] were noticed by Viollet-le-Duc, but that the true amount of the divergence was not apprehended by him, just as the divergence at Amiens escaped his notice entirely.” This fact demonstrates that the purpose of the refinement was remain invisible to the eye.
The refinements can also be in plan form instead of vertical. Here we see the concavity of the facade of Saint Mark’s Cathedral in Venice. According to Goodyear, “The south transept south gallery parapet has a curve in plan convex to the interior, which has the optical and perspective effect of a curve in elevation.”
In this shot of the vaulting shafts of the transepts at Notre Dame de Paris, note the existence of the two plumb lines that surround the column to the right. These are hanging vertical and show clearly the lean of the column carrying the vault. Goodyear notes that this column is parallel to its twin on the left. He states that “the columns in the north transept galleries lean north, and that all the columns in the south transept galleries lean south. The possibility that the columnar leans are due to careless setting is thus outside the range of probabilities.”
The Église Saint Aignan in Saint Quentin is rich in these refinements. In the next shot we clearly see the vertical compensations to correct for perspective distortion.
In the closeup, we can actually see where the compensations begin high upon the nave columns. This documentation by Goodyear is essential in understanding how these refinements were meant to work.
The fact that the medieval builders could design and execute such subtle refinements without benefit of pre-visualization computers and modeling is amazing to us. How did they plan and execute these adjustments which correct for human vision from distance? We don’t have records from there, but there is evidence from Hellenistic times that may be instructive. At the temple of Apollo at Didyma in Turkey, a mason’s drawing was found etched in the temple wall a few years ago that describes how the mason was to carve a column with the proper curvature.
PJ and I will be shooting the Église Saint Aignan in Saint Quentin this spring. One of my main objectives will be to photograph those deformations. However, with all of the perspective distortions involved with photographing these structures (including those introduced by the camera and the tilt-shift lenses), there are huge technical challenges to accomplishing anything meaningful. This is one reason we are so pleased to have the opportunity to prepare by shooting at the Bryn Athyn Cathedral in December. In this way, the architecture of the church leads us to develop techniques for photography. And these techniques, in turn, allow us to discover more about these sublime imperfections and the intent of the original medieval builders.
Note: I would like to thank my beloved niece, Aubrey Elizabeth Hanson, for finding me a copy of the Didyma drawing. She was trained in classics at Loyala Marymount and just completed her graduate work in Museum Studies at Johns Hopkins University. If anyone wants a bright and willing employee in this field, she’s your candidate!