Restoration in an Open Workshop

Revealing the Secrets of a 17th Century Masterpiece

December 15, 2009

For more than a year from August 2007 through October 2008 museum visitors of the Statens Museum for Kunst, the Danish National Gallery in Copenhagen, were able to experience an open conservation studio in the exhibition area. The reason for bringing the conservators and all their equipment into the exhibition rooms of the museum was the conservation, restoration and technical research of Jacob Jordaens’ (1593–1678) early masterpiece "The Tribute Money. Peter Finding the Silver Coin in the Mouth of the Fish", also known as "The Ferry Boat to Antwerp". The process of restoring the painting and investigating the painting technique, materials, history of conservation and provenance of the artwork turned out to reveal unexpected and so far unknown aspects about the genesis of this large masterwork, painted in oil on a canvas measuring 280 × 467 cm.

Technical investigations reveal hidden figure

Throughout the project, the painting was extensively examined through a number of different analytical methods. With a stereomicroscope, partly donated by Leica Microsystems, x-radiography, Infrared Imaging (IR), Scanning Electron Microscopy (SEM-EDX), Fourier Transform Infrared Spectroscopy (FTIR) and Gas Chromatography Mass Spectrometry (GCMS) conservators and conservation scientists have investigated and analysed the paint surface, paint- and ground layers, pigment particles, composition, binding media and canvas support. The project was supported with a Getty Conservation Grant from the Getty Foundation and was closely followed by an international advisory body of experts within conservation, art history and the natural sciences.

The digital x-radiograph generated an entirely new realisation of how the masterpiece originally evolved: hidden below a cloud in the sky between the sail and the men to the right of the disciple Peter are the complete features of a painted woman. The woman belongs to a motif very similar to the painting we see today and is part of a completed but less extended version of "The Ferry Boat to Antwerp" initially carried out by Jordaens. He must then have changed his mind and expanded the painting in four successive stages. While originally commenced on a much smaller scale on two pieces of canvas sewed together, our painting is composed of eight pieces of canvas of varying size and quality.

Fig. 1: The microscopic work in the open workshop in the museum gallery

Disseminating knowledge to museum visitors through a microscope

The museum decided on the open workshop because, as a National Gallery, it feels an obligation to explain to the public how our cultural heritage is researched and cared for. Another goal was to present all aspects of the conservator’s job – from investigating and preserving the artworks to developing ideas for using cultural resources. During the open workshop visitors were able to follow the work of the conservators live on a 50'' plasma screen connected to the stereo microscope. This allowed the visitors to experience the complexity of the paint surface as closely as the conservators.

Fig. 2: X-radiograph (detail) with the revealed head of a woman painted over.

Paint surface phenomena identified

The stereo microscope equipped with a 150 mm objective for large working distances and a floor stand with a flexible swivel arm for horizontal and vertical manoeuvrability was used for the examination and analysis of the paint surface before, during and after the restoration process.

When cleaning the aged and yellowed varnish layers –across some fourteen square metres – as well as the discoloured retouches, the stereo microscope was used extensively in order to continuously distinguish between original paint and later alterations. Numerous areas of blanched paint and varnish marred the appearance of the painting extensively, many of the faded retouches being evidence of earlier conservators’ work. Blanched areas, both in the varnish and in some areas of the paint, further added to the hazy and dull appearance of the composition’s details. After the cleaning, extensive retouching was needed to close lacunae and adjust transparent or abraded areas in order to give this majestic and spectacular painting the presentation it deserves.

The utility of the microscope was also applied in localising phenomena such as saponifications protruding through the surface of the painting caused by molecular changes in the lead white pigments of the ground layers. This phenomenon reveals itself in lead soap formations developing in the ground layers eventually forcing the growing formations to penetrate the paint, appearing on the surface of the painting as small whitish dots 100 mm across.

Fig. 3: Saponifications in the paint surface visible as tiny white spots penetrating the paint layers

A puzzle of canvas pieces and grounds

An in-depth study of the various ground layers applied during the four stages of the painting process was carried out analysing and photographing a number of cross-sections with a research microscope equipped with a digital FireWire color camera system. This was done to gain insight into the structure and composition of the grounds on all eight pieces of canvas and thus more comprehensively understand the complex development of the painting. Samples from the eight canvas sections have shown that the composition of the grounds differs between the four stages of the painting process, confirming the sequence of Jordaens’ enlargement of the painting.

The research on Jordaens’ priming technique and the complexity of the ground layers in "The Ferry Boat to Antwerp" is described in detail by Bredal, Filtenborg, Verhave and Wadum in the article "Determining trends and Developments in Jordaens’ Priming techniques", published in 2010 in the book "Jacob Jordaens, a painter of great distinction: current research on his œuvre" – a new volume in the series of Cultural and Interdisciplinary Studies in Art (ed. Muench & Pataki) Stuttgart, ibidem-Verlag.

Fig. 4a, b: Two cross-sections from “The Ferry Boat to Antwerp” (magnification 100x). 4a shows a cross-section from stage 1 in the painting process (belonging to the painting section with the now hidden woman).
4b is a cross-section from stage 3 in the painting process. The samples clearly show the discrepancy in pigment composition in the two double grounds.

Questions answered and raised

The art historical research has focused on the painting’s provenance in the context of the modes of thought and values of the time. The painting is also a deposit of the society of the 17th century, defined by conventions of its time that were influenced by economy, religion, culture and politics, as well as the relationship between artist and client. The research has outlined the journey of the painting from Jordaens’ Antwerp studio to a major house in Amsterdam’s centre, to a remote Swedish manor house before reaching its final destination in Copenhagen in the early 20th century. The relation between Jordaens’ enlargements of the painting in four stages and the original intention of its hanging is still not fully understood.

The project has provided new insight into Jordaens’ artistic and technical development and the origin of the 400-year-old painting. The in-depth study of the paintings provenance, painting technique and conservation history has answered many questions, while new ones have been raised throughout the project. The puzzle with the eight pieces of canvas was resolved as a result of the extensive technical analysis of the painting including the thorough research on the ground layers as well as a Carbon 14 dating of one of the canvas pieces, but there are still questions to be answered about exactly how the painting evolved and why Jordaens made the changes that he did.

The restoration was accompanied by a large and fully illustrated book which goes even deeper under the surface and lays out the various approaches and results of the most recent research, giving a thorough picture of Jordaens, his works and his time. Articles by: Troels Filtenborg, Lars Hendrikman, Badeloch Noldus, Karsten Ohrt, Eva de la Fuente Pedersen, Annefloor Schlotter, Johanneke H. Verhave, and Jørgen Wadum. "Jordaens. The Making of a Masterpiece", 120 pages, ISBN 978-87-92023-26-1.

The book was made possible thanks to the support of The Getty Foundation and was published in collaboration with the Bonnefantenmuseum, where a comparable yet expanded focus exhibition was staged early in 2009.

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