The Parishioners Needed Light

According to a Catholic critic writing in 1842, people hurried up the altar steps at Bry-sur-MarneBry-sur-Marne, France×A town on the River Marne, just east of Paris. Daguerre’s surviving diorama is in the church of Saint-Gervais-Saint-Protais.Open in Google Maps ↗ after a service and insisted that the curtain be opened again. They wanted a closer look at Louis Daguerre's dioramaDiorama×Wikipedia defines a diorama as “a replica of a scene, typically a three-dimensional model either full-sized or miniature.” The name originally described Daguerre’s painted scenes, where changing light created the illusion of depth and movement.Wikipedia · Diorama ↗.

Abbé Duchaine acknowledged Daguerre's talent and generosity, but thought this a poor use of a sanctuary. A church should encourage religious feeling; this attraction chiefly encouraged curiosity. Even the curtain, opening and closing around the service, belonged to a spectacle.

The object of his complaint still occupies the church of Saint-Gervais-Saint-Protais, in a town just east of Paris. Behind the altar, Daguerre painted the continuation of the building into a much larger Gothic church. Arcades and columns receded towards distant windows. A modest parish acquired a monumental nave without having to build one.

Duchaine also had a practical objection. Daguerre needed darkness to make his illuminated architecture convincing. The parishioners needed light. The painter had made the church gloomy, the critic wrote, yet could not exclude enough daylight to achieve his intended effect. Seen from the entrance, the Gothic interior seemed wrapped in a bluish cloud. One had to approach the choir rail to understand it. Nor did the meeting of a simple modern church and a grand Gothic one please him. A Nativity, with its stable, angels and shepherds, would have been a happier choice.

A church around the picture

Daguerre altered the building as well as the canvas.

He had moved to Bry in 1840, into a large house opposite the church. By then his name was internationally associated with the daguerreotype, the photographic process announced in 1839. He had spent years before that making painted illusions for paying audiences.

At Bry, with support from the local châtelaine, Geneviève de Rigny, he brought that work into the parish church. The choir was extended by about four metres to accommodate the diorama. He gave the work to the town in 1842.

A skylight admitted daylight from above. Openings behind the canvas supplied light from the other side; curtains controlled and concealed it. Some windows in the nave were darkened. The chancel walls acquired black and dark-green imitation marble, and real life-size statues stood in niches beside the painted architecture. Wood panelling and heavy curtains helped join the actual church to the church on the cloth.

The effect needed that surrounding work. A picture that was obviously hung on a brightly lit wall would announce its flatness. Here the viewer had to accept a continuous space, while the source of its illumination remained out of sight. The painting itself was assembled from three upright strips of fine linen, supported on a frame with curved crossbars.

A seat in the machine

Daguerre had developed the commercial Diorama with another painter, Charles-Marie Bouton. An August 1822 share certificate bears both their signatures. In return for a thousand francs, its holder was entitled to a two-hundred-and-fiftieth share of the net profits, reckoned from the Paris exhibition's opening on 11 July.

Bouton and Daguerre supplied the pictures. Edward Planta's 1827 guide to Paris described a small theatre whose whole spectator area revolved at intervals of a quarter of an hour. As one picture went out of view, another arrived. The paintings were later exhibited in London. In Paris the attraction opened from ten until four; admission was two francs and thirty centimes.

The turning room and the changing light did different jobs. The room carried the audience between picture chambers. Within each chamber, the large painting stayed in place while its illumination changed.

At Bry there was one painted extension behind the altar. Its changing appearance depended on the daylight reaching it while the congregation remained in the nave.

Painting for the other side

The technique developed over the years. In 1839 Daguerre published instructions for his mature method of painting and lighting, naming such later subjects as a Midnight Mass and a landslide in the valley of Goldau. Figures could appear where empty chairs had been visible; fallen rocks could replace an intact landscape. These were changes within a stationary painting.

He began with cloth. Percale or calico should have an even weave and be wide enough to require few seams. A join that escaped notice under ordinary illumination could betray itself when light passed through it. Both sides received parchment glue before the painting began.

For the brighter effect on the front, the artist preserved the whiteness of the fabric. Thick opaque paint would obstruct the second effect. Daguerre recommended oil-ground colours applied with spirits, in a manner resembling watercolour. Light reflected from the front made that painting visible.

The reverse was worked with light coming through from the front, so the painter could see where the existing forms lay. He could preserve them or counteract them with a second arrangement of tones. White and black established differences of opacity; transparent coloured glazes followed. When illumination came from behind, this additional work changed what the viewer saw through the cloth.

Light could be admitted to one part of the picture.

Daguerre described masking rear illumination so that it reached only a selected area. Windows behind the painting should stand at least two metres away, leaving room to modify the light with coloured screens. Front and rear illumination could be combined, and even a weakly tinted filter could alter the result.

The daylight itself varied. A whitish sky was preferable, Daguerre wrote. A blue sky strengthened cool colours; warmer light favoured yellows and reds. Shutters and screens could regulate that supply, but its colour did not remain constant from morning to evening.

At Bry, the surviving material evidence is more restricted than the general recipe. Examination during restoration found traces of original white and pink reverse paint on the central strip. The French heritage record identifies that strip as the part worked on the back to produce the changing effects. The whole imagined church was not necessarily a second complete painting waiting behind the first.

A closer look · 2:20 · English

Beyond the real altar

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Another layer of canvas

The diorama survived, but its optical purpose became less secure. It spent long periods behind a curtain. Protection as a historic monument in 1913 did not prevent later interventions from treating it as a conventional painting.

In 1950 the back was scraped and the work was reinforced with another canvas. This strengthened support at the cost of transparency. Later campaigns added further changes. The painted church could remain recognisable while the light that was supposed to pass through it was blocked.

The conservation campaign begun in 2006 brought the two requirements together again. Twelve conservators worked on the painting from 2007. They removed later overpainting, discoloured varnish and the heavy linen lining, repaired damage and supported the original with a very light monofilament polyester fabric that would let light through.

The surrounding church was also restored. Darker decoration returned, along with the statues and curtains. Modern protective glazing and adjustable shutters helped regulate heat as well as illumination. The painting was reinstalled in 2013.

There was a limit to that recovery. Simon Warner, reporting on the reopening, noted that earlier conservation had already destroyed details on the reverse. Transparency could be revived without recovering every form that Daguerre had painted there. Modern controlled lighting can demonstrate the principle; it cannot supply the missing paint.