Presentation of Jean-Baptiste Dumas & Jean-François Persoz at the Academie des SciencesJean-Baptiste DumasJean-François PersozFrench Academy of Scienceschemical analysisDumas Persoz 1851Jean-Baptiste-Antoine LassusSainte-Chapelle

Notre-Dame de Paris

Eugène Viollet-le-DucRestoration of Notre-DameFélix DubanConseil des Bâtiments PublicsSainte-Chapelle's recolouring project

On Monday 10^th of November 1851, the chemists Jean-Baptiste Dumas and Jean-François Persozgave a presentation at the Académie des Sciences in Paris to expose the results of their chemical analysis of a “13^th century wall painting found at the Sainte-Chapelle” . This study, the first in France using heritage science techniques applied to colours of the past, had been ordered by the architect Jean-Baptiste Lassus on March 26^th, 1850. At that time, Lassus had been directing the building site of the Sainte-Chapelle for a year, in parallel with that of Notre-Dame he had been conducting with Eugène Viollet-le-Duc since 1844. Félix Duban, the architect in charge of the Sainte-Chapelle project since the decision of the restoration of the chapel by the Conseil des Bâtiments Publics in 1836, left its supervision to fully devoted himself to the restoration of the Louvre he had started in October 1848.

pigmentpainting techniquewall paintingDiscovery of a medieval wall painting in the Sainte ChapelleFrench RevolutionCharles PercierwatercolourpolychromyCroquis faits au Musée des Monuments français

Percier

Unprecedented research about medieval polychromy had already been conducted at the Sainte-Chapelle before Dumas and Persoz were called to identify, with “modern chemistry guidance”, the pigments and painting techniques used in the medieval wall painting discovered in July 1849. Just after the French Revolution, architect Charles Percier, despite his chromophobe neoclassical taste, recorded in watercolour the first evidence of the indoor polychromy of the Sainte-Chapelle.

Commission for Historical MonumentsProsper MériméePsautier dit de saint Louis

Vue intérieure de la Sainte-Chapelle

Vivet & Coencaustic paintingLudovic Vitet

Following his footsteps, Duban and Lassus developed such a meticulous archaeological approach to the coloured decoration of the chapel that their methodology was described as exemplary by the Commission for Historical Monuments directed at that time by Prosper Mérimée. They first conducted a comprehensive recording of paint traces, as Duban wrote it in a letter dated from May 4^th 1841, “with the closest possible fidelity to the original design choice for decoration”. Then, to confirm their field data, they consulted the 13^th century Psalter of Saint Louis to compare the colours of its illuminations with the existing polychromy of the chapel. On October 20^th, 1843, Duban finally submitted to the administration an “estimate cost for the restoration of the interior decoration based on the work executed up to this day”. The company Vivet & Co, specialised in encaustic painting, was appointed for this task, on the advice of Ludovic Vitet.

Yellow ochreRed ochreRed lacquerCopper resinGoldUltramarineLead whiteMiniumcoatingPantheon

Louis Jacques ThénardJean DarcetAntoine-Jean Gros

Dumas and Persoz thus chemically identified “the nature of the colours and the coatings used to fix them”: yellow ochre , red ochre, red lacquer, copper resin, gold, ultramarine, lead white and minium, applied with “a greasy and resinous coating” similar, they claimed, to the one used on the Pantheon in 1813 by chemists Louis-Jacques Thenard and Jean d’Arcet at the request of Antoine-Jean Gros. 

The Sainte-Chapelle recolouring project, with all its experiments, became a truly innovative laboratory for 19^th-century studies of medieval polychrome architecture and an inspiration for colourful Neo-Gothic aesthetics in France as well as in Great Britain. Augustus Pugin certainly admired the Sainte-Chapelle’s “glorious recolouring” on a visit in Paris in 1844. John Gregory Crace and William Burges, respectively in 1846 and 1853, also expressed great admiration about the colours of Duban’s architecture. In many ways, this restoration site anticipated modern attitudes towards colour heritage policies and sciences across Europe.