Conservation DistList Archives [Date] [Subject] [Author] [SEARCH]

Subject: Studies in Conservation

Studies in Conservation

From: Chandra L. Reedy <clreedy<-a>
Date: Monday, May 5, 2014
Volume 59(3) (May 2014) of Studies in Conservation was recently
published and is now being distributed to IIC (International
Institute for Conservation) members and institutional subscribers.
It contains the following six papers:

    "A novel visualization tool for art history and conservation:
    Automated colorization of black and white archival photographs
    of works of art"

        Sotirios A. Tsaftaris
        IMT, Institute for Advanced Studies
        Lucca, Italy

        Francesca Casadio
        The Art Institute of Chicago
        Chicago, IL, USA

        Jean-Louis Andral
        Musee Picasso
        Antibes, France

        Aggelos K. Katsaggelos
        Department of Electrical Engineering and Computer Science
        Robert McCormick School of Engineering and Applied Science,
        Northwestern University, Evanston, IL, USA

        This paper describes the use of a customized algorithm for
        the colorization of historical black and white photographs
        documenting earlier states of paintings.  This study
        specifically focuses on Pablo Picasso's mid-century
        Mediterranean masterpiece La Joie de Vivre, 1946 (Musee
        Picasso, Antibes, France).  The custom-designed algorithm
        allows computer-controlled spreading of color information on
        a digital image of black and white historical photographs to
        obtain accurate color renditions.  Expert observation of the
        present state of the painting, coupled with stratigraphic
        information from cross sections allows the attribution of
        color information to selected pixels in the digitized
        images.  The algorithm uses the localized color information
        and the grayscale intensities of the black and white
        historical photographs to formulate a set of equations for
        the missing color values of the remaining pixels.  The
        computational resolution of such equations allows an
        accurate colorization that preserves brushwork and shading.
        This new method is proposed as a valuable alternative to the
        use of commercial software to apply flat areas of color,
        which is currently the most common practice for colorization
        efforts in the conservation community.  Availability of such
        colorized images enhances the art-historical understanding
        of the works and might lead to better-informed treatment.

    "Material properties of historic parchment: A reference
    collection survey"

        Alenka Mozir, Irena Kralj Cigic, Marjan Marinsek
        Faculty of Chemistry and Chemical Technology
        University of Ljubljana, Ljubljana, Slovenia

        Matija Strlic
        Centre for Sustainable Heritage
        The Bartlett School of Graduate Studies, University College
        London, UK

        Historic parchment is a complex biological material, and due
        to various methods of production or inks used, unknown
        environmental histories of objects and heterogeneous nature
        of animal skin, it represents a particular analytical
        challenge.  Due to the number of variables it is likely that
        patterns in degradation of these historic objects can only
        be revealed by surveying the material properties of a
        significant number of real objects.  In this work, a
        sacrificial collection of approximately 100 historic
        parchments (fifteenth to twentieth century) was
        characterized using a range of techniques available to
        conservation practitioners that can usefully be used to
        reliably and rapidly characterize parchment.  We focused on
        micro-destructive methods, such as shrinkage temperature
        (Ts), as the most widely used indicator of parchment
        degradation.  Lipid content, roughness, and ink pH were
        additionally measured, while a limited number of samples
        containing iron gall ink were also examined using scanning
        electron microscopy (SEM) and SEM-EDX, to explore the
        distribution of ink components.  Even in the absence of
        detailed environmental histories, it is possible to
        acknowledge the significance of the effect of iron gall ink
        and its acidity, and of lipids on parchment degradation, as
        measured using Ts.  This research reports valuable reference
        data, while the collection remains accessible for further
        research.

    "A multi-analytical approach to the examination of
    nineteenth-century European wallpapers in Vasiq-Ansari House in
    Isfahan, Iran"

        Parviz Holakooei, Amir-Hossein Karimy
        Faculty of Conservation and Restoration of Historic
        Properties
        Art University of Isfahan, Isfahan, Iran

        Carmela Vaccaro
        Department of Physics and Earth Sciences
        University of Ferrara, Ferrara, Italy

        In the nineteenth century, imported wallpapers covered
        interior walls of Persian palaces and mansions, of which
        Vasiq-Ansari House in Isfahan, Iran, exhibits very highly
        elaborated examples.  In this study, micro-Raman
        spectroscopy, scanning electron microscopy, energy
        dispersive X-ray spectroscopy, ultraviolet-visible
        spectroscopy, and light microscopy were used to identify
        pigments and other materials used in the wallpapers of
        Vasiq-Ansari House.  Results indicated that chrome yellow,
        artificial ultramarine blue, brass metallic leaf, an organic
        red dyestuff (probably cochineal), and a copper-based green
        were used as colourants in the wallpapers.  Different shades
        of brown were achieved by mixing various combinations of red
        lead, carbon black, and calcium carbonate.  The white
        calcium carbonate was also used as a ground layer, applied
        to a paper support composed of bast and softwood fibres.
        Based on knowledge of the materials used, these wallpapers
        are most probably manufactured from the mid- to
        late-nineteenth century.

    "Enamel insert restorations on Limoges painted enamels: A study
    on a remarkable nineteenth-century restoration technique with
    particular attention to the original paillon designs"

        Birgit Schwahn
        Private Conservator of Archaeological, Ethnographic, and
        Decorative Arts Objects,
        Bad Kreuznach, Germany

        Two sixteenth-century Limoges painted enamel plaques by
        Leonard Limosin in the collection of the J. Paul Getty
        Museum, Los Angeles, show a remarkable restoration technique
        consisting of separately enameled pieces that have been
        inserted into areas where original enamel was lost.  A
        detailed investigation of the two plaques brought
        information about this former restoration method and the
        materials used.  Investigation included optical microscopy,
        UV-A examination, and X-radiography for identification and
        mapping of the insert restorations, scanning electron
        microscopy with energy dispersive X-ray spectroscopy,
        Fourier transform infrared spectroscopy, and gas
        chromatography-mass spectroscopy for analyzing organic
        restoration material as well as X-ray fluorescence for
        studying the enamel compositions.  A survey of six other
        Limoges painted enamel collections in the USA was carried
        out, which revealed many more of these insert restorations
        and indicated particular damages related to the so-called
        paillon designs on silver or gold foils.  A literature
        review was undertaken focusing on possible causes of the
        damage as well as on persons and workshops that may have
        executed the insert restorations.

    "Painting Hinemihi by numbers: Peoples-based conservation and
    the paint analysis of Hinemihi's carvings"

        Dean Sully
        University College London
        Institute of Archaeology, London, UK

        Isabel Pombo Cardoso
        Departamento de Conservacao e Restauro
        Faculdade de Ciencias e Tecnologia da Universidade Nova de
        Lisboa, Lisbon, Portugal
        (Department of Conservation and Restoration, Faculty of
        Science and Technology, New University of Lisbon)

        This study describes the analysis of paint samples from
        carvings belonging to Hinemihi, the Maori meeting house,
        Clandon Park, Surrey, UK.  The assessment of physical
        evidence contained within Hinemihi's built fabric (along
        with historiographic research of archival sources and oral
        histories) has formed a key part of the information
        gathering process during the current conservation project.
        The production of such data provides an opportunity for a
        dialogue that is essential for effective decision-making
        within participatory conservation projects.  From this, it
        is evident that the use of paint analysis, in deciding the
        eventual painted scheme for a restored Hinemihi, is settled
        within a broader dialogue about the conception, use, and
        management of Hinemihi as a Maori cultural centre, as built
        heritage, and as an object of conservation.  Therefore, the
        value of material analysis is considered in relation to the
        potential that this information has to engage a community of
        users in designing an effective conservation response that
        seeks to balance the opportunities and constraints of the
        cultural and physical landscapes that surround Hinemihi and
        Clandon Park.

    "Conservation of chemically degraded waterlogged wood with
    sugars"

        Anthony Kennedy, Edward Ross Pennington
        Department of Chemistry
        East Carolina University, Greenville, NC, USA

        The effectiveness of two non-reducing sugars, both analogues
        of sucrose, to conserve degraded waterlogged wood was
        examined.  The two sugars examined are trehalose and
        sucralose, both stable and relatively unreactive.  The
        ability of these sugars to conserve a series of degraded
        tongue depressors was measured by determining the
        anti-shrink efficiency of each at various concentrations and
        comparing them to sucrose.  The findings of this study
        indicate that both sucralose and trehalose may be effective
        conservation treatments for waterlogged archaeological wood
        and that at moderate concentrations the performance of both
        is comparable to sucrose.  However, sucralose has a lower
        solubility, and concentrations higher than 60% w/v were not
        examined, whereas concentrations of up to 100% w/v of
        trehalose were studied.  At these higher concentrations
        trehalose performed as well, if not better than sucrose,
        although there were crystalline deposits on the wood surface
        at these higher concentrations.  With modifications and
        careful control, both of these sugars may be suitable
        conservation alternatives to sucrose due to their long-term
        stability and resistance to hydrolysis.

If you are an IIC member, you will need to log in via the IIC
website first in order to gain access.  You can do this at

    <URL:https://www.iiconservation.org/user?destination=promoted>

Once logged in via the IIC website you should have access to the
journal via Maney Online, by using the links on the IIC web page.

Institutional members may need to refer to their library for
password information.

Chandra L. Reedy
Editor-in-Chief, Studies in Conservation


                                  ***
                  Conservation DistList Instance 27:44
                   Distributed: Sunday, May 11, 2014
                       Message Id: cdl-27-44-006
                                  ***
Received on Monday, 5 May, 2014

[Search all CoOL documents]


URL: http://
Timestamp:
Retrieved: