J.CAC VOLUME 43 (2018)

Une étude des matériaux et techniques de Marc-Aurèle Fortin

Marie-Claude Corbeil, Elizabeth Moffatt, Claude Belleau, Eric J. Henderson, Jennifer Poulin

A retrospective exhibition of the work of Marc-Aurèle Fortin organized by the Musée national des beaux-arts du Québec provided the opportunity to examine twenty-six paintings executed between 1918 and 1952, along with two artist’s paint boxes attributed to Fortin from the collection of the Montreal Museum of Fine Arts. Samples from the paintings and the paint tubes found in the boxes were analyzed by scanning electron microscopy/energy-dispersive X-ray spectrometry, X-ray diffraction, Fourier transform infrared spectroscopy, Raman spectroscopy, polarised light microscopy and gas chromatography-mass spectrometry. Data on supports, preparation layers, grey and black ground layers and paints are presented here. The painting supports are quite diverse and are sometimes unusual: canvas (linen or cotton), cardboard, wood, fibreboard, metal and linoleum were all identified. The use of poor quality supports is the main conservation problem for Fortin’s paintings, as they may have deteriorated over time or caused alterations to the paint layers. The canvas supports are usually covered with a ground layer, often white in colour, while the rigid supports are not usually prepared, except sometimes those made of cardboard. The composition of the grey and black ground layers, which are characteristic of Fortin, varies from one painting to another, indicating that Fortin did not follow a strict protocol or that he may have employed commercial materials of variable composition. His colours were obtained using a diverse palette: a total of thirty-seven pigments were identified in the twenty-six works studied. Apart from the black ground layers, the binder of which is an oil-modified alkyd resin, Fortin’s paints are mostly oil-based; in some of his later works he also employed casein paints.

Download: JCAC43 Corbeil et al.

J.CAC VOLUME 43 (2018)

The Evolution of Specifications for Limiting Pollutants in Museums and Archives

Jean Tétreault

Since the first pollutant limits for museums and archives emerged in the 1970s, various documents have proposed specifications to guide pollutant control for the protection of heritage collections. Three approaches to avoiding damaging pollutant levels are examined in this paper: specifications based on maximum allowable levels, on dosimeters and on testing products. The evolution of recommended maximum levels of gaseous pollutants is documented, showing that, over time, limits were progressively lowered but then more recently relaxed, and that lists expanded to include more key pollutants. Dosimeters have been developed as an alternate way to characterize pollutant levels, but their use in museums and archives remains limited. Tests that distinguish products that emit damaging pollutants from those that do not have been more widely adopted as a means of selecting appropriate products for use in collection spaces, especially enclosures. To date, evidence to support specifications has often been weak or may not reflect what actually occurs in the museum environment.

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J.CAC VOLUME 43 (2018)

How Preventive Conservation Can Inform a Collections Move: Rehousing the Canadian and European Furniture Collections at the Royal Ontario Museum

Greg Kelley, Melissa Maltby

In 2015, the Royal Ontario Museum undertook the challenge of a large-scale, two-year move of over 26,000 artifacts from temporary storage in the McLaughlin Planetarium to a purpose-renovated facility. Moving such vast and varied collections presented many unique logistical and organizational challenges. An innovative approach to designing the storage facility from the ground up by using 3-D modelling software to pre-visualize the various layouts is described. Designs, materials and rationales for dust covers, custom pallets, moving crates and storage mounts are also discussed. This paper focuses on part of the project – the systematic process of moving and storing over 500 pieces of furniture and wooden objects – as an illustration of how conservation can inform a large collections move.

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J.CAC VOLUME 42 (2017)

Practical Electrochemistry for Conservators and Conservation Scientists: Part I – The Basics of Potential Measurement

Lyndsie Selwyn, W. Ross McKinnon

Electrochemical techniques are used in conservation to identify metals or corrosion products, or to monitor or treat metal objects. Although there are many published reports on these techniques, it is difficult to find practical information on how to get started to use them. This paper provides some of this information for one important application of these techniques, namely measurement of corrosion potential (the potential of an object immersed in a liquid electrolyte with respect to a reference electrode). Topics covered include electrochemical cells, multimeters, electrical connection to objects, electrolytes and, especially, reference electrodes – common types of reference electrodes, how to use, protect and maintain them, and how to troubleshoot problems. Examples are given of measuring corrosion potential and using Pourbaix diagrams.

Download: JCAC42 Selwyn & McKinnon I

J.CAC VOLUME 42 (2017)

Practical Electrochemistry for Conservators and Conservation Scientists: Part II – Characterizing and Treating Corroded Metals

Lyndsie Selwyn, W. Ross McKinnon

Electrochemical techniques can be used to characterize corrosion on a metal object and to reduce the corrosion either to a different compound or back to the metallic state. These techniques involve the flow of electrical current, and so are more involved than the measurement of the potential between an object and a reference electrode in a two-electrode cell. Information is given here for techniques where current flows, including the choice of a third electrode (the counter electrode) and the additional equipment needed (a power supply or potentiostat). Examples are given of methods varying the potential (potentiodynamic), holding the potential constant (potentiostatic), or holding the current constant (galvanostatic). The following aspects are discussed: identifying the features associated with oxygen reduction, associating the peaks in potentiodynamic scans with specific compounds in the corrosion, choosing the potential for treating an object, and estimating the amount of corrosion on an object or a test sample.

Download: JCAC42 Selwyn & McKinnon II

J.CAC VOLUME 42 (2017)

The Treatment of a Catharine Parr Traill Botanical Album

Christine McNair

A treatment was undertaken at the Canadian Conservation Institute to conserve a botanical album compiled by Catharine Parr Traill from the collection of the Peterborough Museum and Archives. The botanical specimens, many detached, were vulnerable to mechanical damage due to the stiffness of the binding. After consultation with conservators at the Canadian Museum of Nature, a treatment method was developed to reattach the detached specimens using micro solvent-set straps of Japanese paper. This solvent-set strapping interfered minimally with the movement of the book’s pages and was comparable to methods used within herbariums. The strips are easily reversible and require minimum moisture and adhesive. Some portions of the specimens were lightly adhered using methyl cellulose. The binding itself was structurally altered by adding a moulded spine hollow in order to improve the opening of the volume and to prevent further mechanical damage.

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J.CAC VOLUME 41 (2016)

Characterization of Artificial Stone Used for Outdoor Monuments and Sculptures in Quebec

Dominique Duguay, Jane Sirois, Melanie Raby, Isabelle Paradis

Artificial stone is often employed in sculptural work and architectural details in Quebec, including many monuments that have fallen into disrepair. During this collaborative project between the Canadian Conservation Institute and the Centre de conservation du Québec, 16 samples were taken from 12 sculptures across Quebec and were analyzed by means of stereomicroscopy, scanning electron microscopy/energy dispersive X-ray spectrometry, thin-section petrography and X-ray diffraction. Some aspects of the analysis, for instance the confirmation of the presence of clinker, proved to be challenging due to the restrictions on sample size required in conservation work. The results indicate that more than half of the sculptures analyzed were hydraulic cement-based artificial stone. The remaining sculptures were made of Coade stone, or lime-, gypsum- or dolomite-containing materials. This research provides a limited survey of artificial stones in Quebec and will help guide conservators in selecting proper treatments for these works by allowing identification and better understanding of the materials.

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J.CAC VOLUME 41 (2016)

Shredded Cedar Bark: A Survey of Past Treatments

Sonia Kata, Carole Dignard

A survey of past treatments for shredded cedar bark was carried out on sixteen objects: two masks from the U’mista Cultural Centre and fourteen similar objects at the Canadian Museum of History (CMH), which had been assessed or treated by the CMH or the Canadian Conservation Institute (CCI) nearly 30 years ago. The objects were examined and evaluated with regard to cedar bark condition, appearance, pH and iron content. Treatments fell into four groups: 1) adhesive consolidation; 2) localized paper supports with adhesives; 3) localized thread wrappings, with or without adhesives; and 4) no treatment, sometimes coupled with a support. Parylene (poly-para-xylylenes) coating was also investigated as CCI carried out tests on cedar bark samples several years ago. Each treatment strategy had some benefits and drawbacks. Iron content was identified as an important factor in condition. A literature review on shredded cedar bark was also conducted to elucidate its properties, processing and conservation.

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J.CAC VOLUME 41 (2016)

Technical Note: Magnetic Mounts for Textile and Leather Objects in a Travelling Exhibit

Amanda Harding

This note describes a method to construct mounts for three objects in a travelling exhibit using rare earth magnets. The objects were made of textile and leather and included an original beaded fire bag, reproduction leather mittens and reproduction leg garters. The mounts for the mittens and leg garters were successful but the mount for the fire bag failed in one context.

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