Presentation & Poster Abstracts
Dark blue titles denote presentation abstracts
Teal titles denote poster abstracts
Teal titles denote poster abstracts
Columbia University Historic Preservation Program
Use of Astringent Persimmon Juice as an Alternative Wood Preservation Treatment
Kat Gardner
Since the 1952 isolation of plumbagin, a bioactive 1, 4-naphthoquinone in Diospyros hebecarpa, dozens of component chemicals and bioactive compounds have been identified and studied in the genus Diospyros. Many of these extractives are now known to be effective fungicides, termiticides, and antibacterial compounds. The genus Diospyros (syn. Persimmon, ebony) is widely distributed in most tropical areas of both hemispheres with over 300 species, with a long cultural and agricultural history in the pacific rim.
The research presented will discuss the potential for an environmentally-friendly wood preservative that is effective against multiple agents, derived from astringent persimmon fruit of Diospyros kaki. A review of current literature will cover both known traditional use as a preservative, patented experimental use, and known information on chemical components and derivatives of Diospyros. Laboratory testing of raw astringent persimmon juice and kakishibu—fermented astringent persimmon juice—will be compared to an uncoated control and a control coated with copper naphthenate, a comparable preservative. These will be applied to seasoned, weathered, and historic wood samples and evaluated in short term exterior weathering, chroma change with age, soil block cultures for fungal testing, and leaching tests. While these tests are defined by ASTM and AWPA standards for testing wood preservatives, their applicability to historic material requires the standards to be modified to fit application method.
Kat Gardner
Since the 1952 isolation of plumbagin, a bioactive 1, 4-naphthoquinone in Diospyros hebecarpa, dozens of component chemicals and bioactive compounds have been identified and studied in the genus Diospyros. Many of these extractives are now known to be effective fungicides, termiticides, and antibacterial compounds. The genus Diospyros (syn. Persimmon, ebony) is widely distributed in most tropical areas of both hemispheres with over 300 species, with a long cultural and agricultural history in the pacific rim.
The research presented will discuss the potential for an environmentally-friendly wood preservative that is effective against multiple agents, derived from astringent persimmon fruit of Diospyros kaki. A review of current literature will cover both known traditional use as a preservative, patented experimental use, and known information on chemical components and derivatives of Diospyros. Laboratory testing of raw astringent persimmon juice and kakishibu—fermented astringent persimmon juice—will be compared to an uncoated control and a control coated with copper naphthenate, a comparable preservative. These will be applied to seasoned, weathered, and historic wood samples and evaluated in short term exterior weathering, chroma change with age, soil block cultures for fungal testing, and leaching tests. While these tests are defined by ASTM and AWPA standards for testing wood preservatives, their applicability to historic material requires the standards to be modified to fit application method.
Harvard University Art Museums, Straus Center for Conservation and Technical Studies
Becoming a Paper Conservator in France: Education and Working Experience
Sophie Barbisan
The National Institute of Cultural Heritage (Inp) is one of the two education programs in France that allows conservators of various specialties to work on masterpieces from museums with the “Musées de France” label. This state school, funded by the French Cultural Ministry, is a five year program, culminating in a Master’s degree in one of the following specialties: ceramics, paper, textiles, furniture, painting, photography and sculpture. This specialization is determined before the student enters graduate school and the educational program is entirely dedicated to the particular specialization.
This paper will introduce the different conservation educations programs in France and will focus on the National Institute of Cultural Heritage. Of particular interest are the partnerships with French museums that allow students access to various collections on which to gain experience. The presentation will then focus specifically on the importance of internships through the example of Ms. Barbisan’s time at the Louvre. Finally, the paper will touch on research carried out in the Inp‘s paper lab, concentrating on the properties of silica gel. This material has been used before as a drying agent to regulate relative humidity. Building on previous research by Maroussia Duranton and Gaëlle Hennion, silica gel was used here in a humidification chamber to reach a very controlled level of relative humidity. This technique allowed for a gentle humidification, useful for fragile media such as gouache or iron-gall ink.
Sophie Barbisan
The National Institute of Cultural Heritage (Inp) is one of the two education programs in France that allows conservators of various specialties to work on masterpieces from museums with the “Musées de France” label. This state school, funded by the French Cultural Ministry, is a five year program, culminating in a Master’s degree in one of the following specialties: ceramics, paper, textiles, furniture, painting, photography and sculpture. This specialization is determined before the student enters graduate school and the educational program is entirely dedicated to the particular specialization.
This paper will introduce the different conservation educations programs in France and will focus on the National Institute of Cultural Heritage. Of particular interest are the partnerships with French museums that allow students access to various collections on which to gain experience. The presentation will then focus specifically on the importance of internships through the example of Ms. Barbisan’s time at the Louvre. Finally, the paper will touch on research carried out in the Inp‘s paper lab, concentrating on the properties of silica gel. This material has been used before as a drying agent to regulate relative humidity. Building on previous research by Maroussia Duranton and Gaëlle Hennion, silica gel was used here in a humidification chamber to reach a very controlled level of relative humidity. This technique allowed for a gentle humidification, useful for fragile media such as gouache or iron-gall ink.
New York University Institute of Fine Arts Master’s Conservation Program
Digital Media in Art: Meaning, Materiality, Digital Forensics Workflows, and Conservation
Amy Brost
Decision-making in time-based media art conservation is guided by a thorough understanding of the identity of the artwork – what qualities or physical elements can be changed or replaced as the work ages, and which cannot. The shared education in conservation methodology across specializations can be brought to bear on the process of acquiring this understanding, which enables the conservator to determine the meaning and significance of the digital media in the artwork. Conservators must also ensure that the physical elements of the work are preserved. These may include diverse display equipment, magnetic or optical media, digital files and more. Together, these efforts form the basis for ethical conservation treatment. This talk will highlight two examples: preservation planning for a work by Kevin & Jennifer McCoy titled “Every Shot, Every Episode” (2001) in the collection of The Metropolitan Museum of Art, and the archiving of Jeremy Blake’s born-digital production files in Fales Library & Special Collections at Bobst Library at New York University. Bobst Library is one of the few cultural heritage institutions in the United States to have a forensic workstation at a time when digital forensics workflows are becoming the recommended practice for managing born-digital materials in archives.
Amy Brost
Decision-making in time-based media art conservation is guided by a thorough understanding of the identity of the artwork – what qualities or physical elements can be changed or replaced as the work ages, and which cannot. The shared education in conservation methodology across specializations can be brought to bear on the process of acquiring this understanding, which enables the conservator to determine the meaning and significance of the digital media in the artwork. Conservators must also ensure that the physical elements of the work are preserved. These may include diverse display equipment, magnetic or optical media, digital files and more. Together, these efforts form the basis for ethical conservation treatment. This talk will highlight two examples: preservation planning for a work by Kevin & Jennifer McCoy titled “Every Shot, Every Episode” (2001) in the collection of The Metropolitan Museum of Art, and the archiving of Jeremy Blake’s born-digital production files in Fales Library & Special Collections at Bobst Library at New York University. Bobst Library is one of the few cultural heritage institutions in the United States to have a forensic workstation at a time when digital forensics workflows are becoming the recommended practice for managing born-digital materials in archives.
Conservation through Conversation: Material and Meaning in the Work of Dario Robleto
Desi Peters
The art of contemporary artist Dario Robleto (b.1972) challenges conservation ethics and practice because he often uses historic and culturally sensitive material as the raw substance for his artworks. Frequently the historic materials are manipulated and transformed into an unrecognizable form. They are thus divorced from any visible connection to their original context. Sensitive to this separation, Dario includes material lists, which he terms “liner notes,” that detail the origins of the artwork’s components and that are, according to the artist, as much a part of the artwork as the object itself. The final work is an amalgam of transformed historic material that has both a new contemporary context represented visually and an original context represented in the liner notes. Robleto’s method, technique, and the nature of the viewer's experience with his works will be introduced, and the materials, technique, and conservation challenges of a single work, A Defeated Soldier Wishes to Walk His Daughter Down the Wedding Aisle, 2004, will be considered. Conservation solutions borne from interviews between the author and artist since 2013 will be presented.
Desi Peters
The art of contemporary artist Dario Robleto (b.1972) challenges conservation ethics and practice because he often uses historic and culturally sensitive material as the raw substance for his artworks. Frequently the historic materials are manipulated and transformed into an unrecognizable form. They are thus divorced from any visible connection to their original context. Sensitive to this separation, Dario includes material lists, which he terms “liner notes,” that detail the origins of the artwork’s components and that are, according to the artist, as much a part of the artwork as the object itself. The final work is an amalgam of transformed historic material that has both a new contemporary context represented visually and an original context represented in the liner notes. Robleto’s method, technique, and the nature of the viewer's experience with his works will be introduced, and the materials, technique, and conservation challenges of a single work, A Defeated Soldier Wishes to Walk His Daughter Down the Wedding Aisle, 2004, will be considered. Conservation solutions borne from interviews between the author and artist since 2013 will be presented.
The Use of Scanning Electron Microscopy & RTI to Detect Surface Abrasion in Dry-Cleaned Plaster
Kathryn Brugioni
Practically all dry-cleaning methods of plaster involve abrasion on some scale. Previous studies of dry-cleaning methods have evaluated the degree of abrasion by imaging test coupons in a scanning electron microscope (SEM) (See Wharton, et al., “A Comparative Study of Silver Cleaning Abrasives,” JAIC, Vol. 29, No. 1 (Spring, 1990). This method does indeed allow the conservator to compare the surface scratching caused by abrasive cleaning; however, this instrumentation is not available to everyone. Furthermore, the resulting photomicrographs show a level of detail which will never be perceptible to the human eye. In the absence of SEM analysis, a more accessible method for measuring surface scratching should be assayed: Reflectance Transformation Imaging (RTI). This study sought to determine the extent to which RTI can detect surface changes not perceptible to the human eye. RTI was used to evaluate abrasion caused by multiple dry-cleaning techniques and materials. These data were compared to SEM photomicrographs, which allowed for a precise measurement of the level of abrasion detectable by each method.
Kathryn Brugioni
Practically all dry-cleaning methods of plaster involve abrasion on some scale. Previous studies of dry-cleaning methods have evaluated the degree of abrasion by imaging test coupons in a scanning electron microscope (SEM) (See Wharton, et al., “A Comparative Study of Silver Cleaning Abrasives,” JAIC, Vol. 29, No. 1 (Spring, 1990). This method does indeed allow the conservator to compare the surface scratching caused by abrasive cleaning; however, this instrumentation is not available to everyone. Furthermore, the resulting photomicrographs show a level of detail which will never be perceptible to the human eye. In the absence of SEM analysis, a more accessible method for measuring surface scratching should be assayed: Reflectance Transformation Imaging (RTI). This study sought to determine the extent to which RTI can detect surface changes not perceptible to the human eye. RTI was used to evaluate abrasion caused by multiple dry-cleaning techniques and materials. These data were compared to SEM photomicrographs, which allowed for a precise measurement of the level of abrasion detectable by each method.
Juggling Priorities: Risk Assessment and Risk Management of Sheila Hicks’s “B-level Tapestries” at the Ford Foundation
Emily Frank
Sheila Hicks, an American-born fiber artist, was commissioned to create two large-scale fiber artworks for the Ford Foundation’s boardroom and auditorium in the 1960s. The Ford Foundation is a non-traditional display context for Sheila Hicks’ work. These artworks were installed in 1966-1967 and were created to be site-specific permanent fixtures. At some point in the following years, the works were treated with a caustic fire retardant that caused slow disintegration of the textile fibers. The artist, in consultation with conservators, concluded that conservation of the damaged works was not an option and agreed to produce replicas using modified materials. These new versions of the works were created in 2013 and 2014 to replace the deteriorated originals. There are a number of material and construction differences between the 1966-1967 and 2013-2014 “B-level Tapestries.” Notably, Sheila Hicks directed the Ford Foundation to destroy the originals after the installation of their replacements. This investigation aims to assess the individual and overall risks to the second iteration of Sheila Hicks’s artworks at the Ford Foundation in the short term (2020), the medium term (2050) and the long term (2100). Additionally, it presents a risk management plan that considers each of these time frames and hypothesizes an acceptable compromise from the perspective of both the conservator and the owner/administrator, while considering the views of the other stakeholders.
Emily Frank
Sheila Hicks, an American-born fiber artist, was commissioned to create two large-scale fiber artworks for the Ford Foundation’s boardroom and auditorium in the 1960s. The Ford Foundation is a non-traditional display context for Sheila Hicks’ work. These artworks were installed in 1966-1967 and were created to be site-specific permanent fixtures. At some point in the following years, the works were treated with a caustic fire retardant that caused slow disintegration of the textile fibers. The artist, in consultation with conservators, concluded that conservation of the damaged works was not an option and agreed to produce replicas using modified materials. These new versions of the works were created in 2013 and 2014 to replace the deteriorated originals. There are a number of material and construction differences between the 1966-1967 and 2013-2014 “B-level Tapestries.” Notably, Sheila Hicks directed the Ford Foundation to destroy the originals after the installation of their replacements. This investigation aims to assess the individual and overall risks to the second iteration of Sheila Hicks’s artworks at the Ford Foundation in the short term (2020), the medium term (2050) and the long term (2100). Additionally, it presents a risk management plan that considers each of these time frames and hypothesizes an acceptable compromise from the perspective of both the conservator and the owner/administrator, while considering the views of the other stakeholders.
Queen's University Art Conservation Program
Fill Materials for Cast Acrylite® Used in Face-Mounted Photographs: Scratch-Repair, Methodology, and Accelerated Aging
Kaslyne R. O’Connor
A primary conservation issue for the sustained use of face-mounted photographs is the long-term stability and inherent susceptibility of the acrylic sheet surface to abrasions. Scratches disfigure the entire surface of the poly(methyl methacrylate) sheet by changing the surface topography and distracting the viewer from the photograph. Scratches on acrylic sheet surfaces can be the result of improper handling, storage, and routine cleaning, and can range in size from micrometers to centimeters in size. The care, storage, and conservation of these acrylic face-mounted photographs have become growing subjects of debate and preservation experiments among the conservation community.
The primary goal of this study is to determine the quality of scratch repairs for acrylic sheeting and their suitability for the conservation and preservation of face-mounted photographs. Mechanical scratches will be made on Acrylite® sheet samples and filled manually with three selected materials (an acrylic copolymer, an ultra-violet curing adhesive, and a two-part epoxy), each displaying effective refractive indices, low viscosities, resistance to yellowing and favourable working times. Samples will be subjected to accelerated thermal and light aging to detect any negative effects on the poly(methyl methacrylate) caused by the application and manipulation of these scratch fillers. Materials used in successful repairs will undergo analytical comparative tests with a spectrophotometer and glossmeter for colour change or surface distortion, as well as visual comparisons of ensuing scratch visibility. The success or failure of the fills will be evaluated according to their ability to reduce the appearance of scratches without negatively impacting the finishing surface.
Kaslyne R. O’Connor
A primary conservation issue for the sustained use of face-mounted photographs is the long-term stability and inherent susceptibility of the acrylic sheet surface to abrasions. Scratches disfigure the entire surface of the poly(methyl methacrylate) sheet by changing the surface topography and distracting the viewer from the photograph. Scratches on acrylic sheet surfaces can be the result of improper handling, storage, and routine cleaning, and can range in size from micrometers to centimeters in size. The care, storage, and conservation of these acrylic face-mounted photographs have become growing subjects of debate and preservation experiments among the conservation community.
The primary goal of this study is to determine the quality of scratch repairs for acrylic sheeting and their suitability for the conservation and preservation of face-mounted photographs. Mechanical scratches will be made on Acrylite® sheet samples and filled manually with three selected materials (an acrylic copolymer, an ultra-violet curing adhesive, and a two-part epoxy), each displaying effective refractive indices, low viscosities, resistance to yellowing and favourable working times. Samples will be subjected to accelerated thermal and light aging to detect any negative effects on the poly(methyl methacrylate) caused by the application and manipulation of these scratch fillers. Materials used in successful repairs will undergo analytical comparative tests with a spectrophotometer and glossmeter for colour change or surface distortion, as well as visual comparisons of ensuing scratch visibility. The success or failure of the fills will be evaluated according to their ability to reduce the appearance of scratches without negatively impacting the finishing surface.
Exploring the Role of the Substrate in the Fading and Reversion Behaviour for Prussian Blue Dye
Sophia Zweifel
The pigment Prussian blue (ferric ferrocyanide) is known to exhibit phototropic behaviour due to its isotropic structure. Under prolonged exposure to light or in the absence of oxygen, Prussian blue will fade to Prussian white as its ferric iron is reduced to the lower oxidation state of ferrous iron. The compound will revert back to Prussian blue when re-exposed to dark, ambient conditions. While the fading and reversion mechanism of Prussian blue is largely understood, these behaviors are complicated by environmental conditions, by the presence of production additives, as well as by the substrate upon which it is suffused. For example, it remains undetermined if a proteinaceous substrate might influence the reduction-oxidation reaction of Prussian blue differently than would a cellulosic substrate. This is particularly important in the case of Prussian blue dye, which was of common use during the nineteenth century.
This study will attempt to analyse the role of the substrate in the fading and reversion of Prussian blue dye by measuring the degree and rate of Prussian blue fading and reversion across samples of different substrates (particularly cotton and silk). The samples will be exposed to light under ambient conditions as well as under anoxia. Colour change and rate will be measured using a portable microfade tester. A secondary set of samples will be exposed under regular and anoxic conditions in an LED light chamber at 100 000 lux over a longer period of time. The colour change of these samples will be measured by a portable spectrophotometer. Additionally, the samples will be analysed qualitatively by Fourier transform infrared spectroscopy in order to identify the chemical change responsible for the fading and reversion Prussian blue dye. Determining the degree and rate of colour change of Prussian blue dye on different substrates will yield significant information that could help refine more specific display guidelines for artifacts, as well as quantify the risks involved in the anoxic treatment of Prussian blue textiles.
Sophia Zweifel
The pigment Prussian blue (ferric ferrocyanide) is known to exhibit phototropic behaviour due to its isotropic structure. Under prolonged exposure to light or in the absence of oxygen, Prussian blue will fade to Prussian white as its ferric iron is reduced to the lower oxidation state of ferrous iron. The compound will revert back to Prussian blue when re-exposed to dark, ambient conditions. While the fading and reversion mechanism of Prussian blue is largely understood, these behaviors are complicated by environmental conditions, by the presence of production additives, as well as by the substrate upon which it is suffused. For example, it remains undetermined if a proteinaceous substrate might influence the reduction-oxidation reaction of Prussian blue differently than would a cellulosic substrate. This is particularly important in the case of Prussian blue dye, which was of common use during the nineteenth century.
This study will attempt to analyse the role of the substrate in the fading and reversion of Prussian blue dye by measuring the degree and rate of Prussian blue fading and reversion across samples of different substrates (particularly cotton and silk). The samples will be exposed to light under ambient conditions as well as under anoxia. Colour change and rate will be measured using a portable microfade tester. A secondary set of samples will be exposed under regular and anoxic conditions in an LED light chamber at 100 000 lux over a longer period of time. The colour change of these samples will be measured by a portable spectrophotometer. Additionally, the samples will be analysed qualitatively by Fourier transform infrared spectroscopy in order to identify the chemical change responsible for the fading and reversion Prussian blue dye. Determining the degree and rate of colour change of Prussian blue dye on different substrates will yield significant information that could help refine more specific display guidelines for artifacts, as well as quantify the risks involved in the anoxic treatment of Prussian blue textiles.
A Comparative Study of Lightfastness in Oil-Based and Soy-Based Printmaking Inks in Works of Art on Paper
Lauren Buttle
After meeting with success in the commercial sector, soy-based inks were introduced to artists in the 1990s as an alternative to their more traditional oil-based counterpart. These inks are advertised as being able to produce brighter colours while maintaining the same quality as oil-based inks. Additionally, they are water-soluble and thus, easier and safer to dispose of. As this medium is relatively new to the art world, this project investigated the structure of these inks and the characteristics that make them usable for printmaking. The lightfast properties of soy-based ink by AKUA® (Intaglio) and traditional oil-based ink from Gamblin® were compared. Four different colours of each type of ink were studied. Samples were made both on Stonehenge printmaking paper to replicate real-life circumstances and on Whatman® Filter paper to isolate any optical changes caused by additives in the paper substrate. The colour of the samples was measured before and after natural and artificial light aging with a spectrophotometer. Fourier transform infrared (FTIR) spectroscopy was also carried out before and after aging to monitored any chemical changes in the material. This study is focused on the longevity and exhibition parameters necessary for conservators to accommodate such new works.
Lauren Buttle
After meeting with success in the commercial sector, soy-based inks were introduced to artists in the 1990s as an alternative to their more traditional oil-based counterpart. These inks are advertised as being able to produce brighter colours while maintaining the same quality as oil-based inks. Additionally, they are water-soluble and thus, easier and safer to dispose of. As this medium is relatively new to the art world, this project investigated the structure of these inks and the characteristics that make them usable for printmaking. The lightfast properties of soy-based ink by AKUA® (Intaglio) and traditional oil-based ink from Gamblin® were compared. Four different colours of each type of ink were studied. Samples were made both on Stonehenge printmaking paper to replicate real-life circumstances and on Whatman® Filter paper to isolate any optical changes caused by additives in the paper substrate. The colour of the samples was measured before and after natural and artificial light aging with a spectrophotometer. Fourier transform infrared (FTIR) spectroscopy was also carried out before and after aging to monitored any chemical changes in the material. This study is focused on the longevity and exhibition parameters necessary for conservators to accommodate such new works.
Investigation of Sodium Dodecyl Sulfate and Hostacor® IT as Flash Rust Inhibitors for Rinsing Archaeological Iron
Megan Doxsey-Whitfield
Flash rusting is a common problem for conservators treating wet archaeological iron. After a desalination treatment, the iron object must be rinsed, which typically results in flash rusting. Corrosion inhibitors are not commonly used to prevent this, but could be an effective addition to the treatment procedure. Sodium dodecyl sulfate (SDS) is the active component in Orvus® WA paste, an anionic surfactant cleaner found in many conservation laboratories. SDS has been used as a corrosion inhibitor for copper and nickel in acidic solutions. This study has investigated whether SDS is a good corrosion inhibitor for iron by comparison with Hostacor® IT, an industrial product known to be effective. SDS was chosen for testing as an alternative to Hostacor® IT because Orvus® WA paste is more cost effective, more readily available, and less hazardous to the environment. This experiment examined the effectiveness of four concentrations of SDS in water, a 1% Hostacor® IT (v/v) in water solution, and a control of water with no corrosion inhibitor. The metal coupons were evaluated visually and photographed every hour over a 12-hour period to assess the development of flash rusting. Based on pilot testing, SDS is not as effective as Hostacor® IT at preventing rust formation, but it is more effective than water alone for short-term rinses. Full results about all the tests can be found on the poster. These findings could help conservators design rinse procedures that reduce the occurrence of flash rusting on archaeological iron by adding Orvus® WA paste at the rinse stage.
Megan Doxsey-Whitfield
Flash rusting is a common problem for conservators treating wet archaeological iron. After a desalination treatment, the iron object must be rinsed, which typically results in flash rusting. Corrosion inhibitors are not commonly used to prevent this, but could be an effective addition to the treatment procedure. Sodium dodecyl sulfate (SDS) is the active component in Orvus® WA paste, an anionic surfactant cleaner found in many conservation laboratories. SDS has been used as a corrosion inhibitor for copper and nickel in acidic solutions. This study has investigated whether SDS is a good corrosion inhibitor for iron by comparison with Hostacor® IT, an industrial product known to be effective. SDS was chosen for testing as an alternative to Hostacor® IT because Orvus® WA paste is more cost effective, more readily available, and less hazardous to the environment. This experiment examined the effectiveness of four concentrations of SDS in water, a 1% Hostacor® IT (v/v) in water solution, and a control of water with no corrosion inhibitor. The metal coupons were evaluated visually and photographed every hour over a 12-hour period to assess the development of flash rusting. Based on pilot testing, SDS is not as effective as Hostacor® IT at preventing rust formation, but it is more effective than water alone for short-term rinses. Full results about all the tests can be found on the poster. These findings could help conservators design rinse procedures that reduce the occurrence of flash rusting on archaeological iron by adding Orvus® WA paste at the rinse stage.
Examining the Effect of Relative Humidity on Mammoth Molars
Daniel Doyle
Museum and natural history collections are very sensitive to fluctuations in relative humidity. Due to a high degree of structural anisotropy, mammoth molars are potentially damaged by such fluctuations. Upon excavation, mammoth molars often undergo rapid acclimatization to the ambient relative humidity (RH), with resulting delamination and cracking observed. Research conducted by Samantha Fisher in the Art Conservation Program at Queen’s University, Kingston, Ontario, in 2014 on mammoth molars found that cracks widen and extend after exposure to 75%RH, cracks continue to extend after the drop to 35%RH, cement adsorbs and desorbs faster than enamel. To further understand the changes which occur during significant drops to low RH, such as during the initial excavation and drying of the molars, a single cycle was undertaken from ambient RH to a low 11%RH using a lithium chloride salt. Weight changes indicating the adsorption and desorption of water from the teeth were measured to better understand the internal moisture change, and to identify when the molars reached equilibrium. The resulting dimensional changes and crack propagation were measured using ImageJ analysis software, as well as physical crack measurement. This is only one of a very limited number of studies into the effects of relative humidity on natural history collections. As such, a survey of current storage conditions for natural history collections was undertaken to better understand current practices and propose preventative steps.
Daniel Doyle
Museum and natural history collections are very sensitive to fluctuations in relative humidity. Due to a high degree of structural anisotropy, mammoth molars are potentially damaged by such fluctuations. Upon excavation, mammoth molars often undergo rapid acclimatization to the ambient relative humidity (RH), with resulting delamination and cracking observed. Research conducted by Samantha Fisher in the Art Conservation Program at Queen’s University, Kingston, Ontario, in 2014 on mammoth molars found that cracks widen and extend after exposure to 75%RH, cracks continue to extend after the drop to 35%RH, cement adsorbs and desorbs faster than enamel. To further understand the changes which occur during significant drops to low RH, such as during the initial excavation and drying of the molars, a single cycle was undertaken from ambient RH to a low 11%RH using a lithium chloride salt. Weight changes indicating the adsorption and desorption of water from the teeth were measured to better understand the internal moisture change, and to identify when the molars reached equilibrium. The resulting dimensional changes and crack propagation were measured using ImageJ analysis software, as well as physical crack measurement. This is only one of a very limited number of studies into the effects of relative humidity on natural history collections. As such, a survey of current storage conditions for natural history collections was undertaken to better understand current practices and propose preventative steps.
Examining Effects of Ammonium Citrate Immersions on Paper
Laura Hashimoto
This research emerged from Antoinette Dwan’s studies and techniques on the use of the chelating agent ammonium citrate for the removal of acidic soiling and staining from paper. Whatman no. 40 filter paper, naturally aged blue-dyed rag ledger, and naturally aged newsprint were subjected to immersions in either 1%, 3%, or 10% w/v triammonium citrate solutions. Samples were subjected to accelerated thermal aging and compared to their control and wash control samples. Mechanical strength and colour change were assessed with zero-span tensile testing and spectrophotometry respectively. The research aimed to compare the results of ammonium citrate immersions to established aqueous deacidification washing practice in paper conservation.
Laura Hashimoto
This research emerged from Antoinette Dwan’s studies and techniques on the use of the chelating agent ammonium citrate for the removal of acidic soiling and staining from paper. Whatman no. 40 filter paper, naturally aged blue-dyed rag ledger, and naturally aged newsprint were subjected to immersions in either 1%, 3%, or 10% w/v triammonium citrate solutions. Samples were subjected to accelerated thermal aging and compared to their control and wash control samples. Mechanical strength and colour change were assessed with zero-span tensile testing and spectrophotometry respectively. The research aimed to compare the results of ammonium citrate immersions to established aqueous deacidification washing practice in paper conservation.
Investigating the Effects of Silicone Solvents and Silicone-based Microemulsions on Paper
Natasa Krsmanovic
This work examines the use of Cyclomethicone D4 (octamethylcyclotetrasiloxane), a silicone solvent, and Cyclomethicone D4 based microemulsions on paper substrates. The study consisted of 3 phases. Firstly, the effects of the solvent on a variety of paper types are analyzed for colour change, and residue. Morphology changes of the paper surfaces were visually examined under magnification, reflected light, and UV light. SEM was used to analyze the papers for solvent residue. The second phase evaluated the appropriateness of silicone-based microemulsions for localized aqueous cleaning of paper. Paper dyed with a highly water-soluble colourent were immersed in water, silicone solvent, or microemulsions of the silicone solvent, Ecosurf EH-3, and water (20% and 50% w/w) and removal of the dye was measured. Finally, the third phase investigated if silicone-based microemulsions can be used to locally extract water-soluble material from paper without wetting out the surface if incorporated into a gel. The emulsions were absorbed into a rigid gel of 2% Gellan Gum in water. The microemulsion saturated gel was applied to samples of paper dyed with a highly water-soluble colorant and removal of the colorant assessed.
Natasa Krsmanovic
This work examines the use of Cyclomethicone D4 (octamethylcyclotetrasiloxane), a silicone solvent, and Cyclomethicone D4 based microemulsions on paper substrates. The study consisted of 3 phases. Firstly, the effects of the solvent on a variety of paper types are analyzed for colour change, and residue. Morphology changes of the paper surfaces were visually examined under magnification, reflected light, and UV light. SEM was used to analyze the papers for solvent residue. The second phase evaluated the appropriateness of silicone-based microemulsions for localized aqueous cleaning of paper. Paper dyed with a highly water-soluble colourent were immersed in water, silicone solvent, or microemulsions of the silicone solvent, Ecosurf EH-3, and water (20% and 50% w/w) and removal of the dye was measured. Finally, the third phase investigated if silicone-based microemulsions can be used to locally extract water-soluble material from paper without wetting out the surface if incorporated into a gel. The emulsions were absorbed into a rigid gel of 2% Gellan Gum in water. The microemulsion saturated gel was applied to samples of paper dyed with a highly water-soluble colorant and removal of the colorant assessed.
Gatorfoam to Improve the Structural Integrity of Paintings: Prevention of Damage from In-House Handling
Bethany Jo Mikelait
Gatorfoam is a board of polystyrene foam laminated between two panels of proprietary resin-coated wood fibre veneer. A study was conducted to investigate the function and effectiveness of Gatorfoam in paintings conservation as a rigid, direct-contact support placed between the stretcher and the canvas. This material in theory would provide a stable physical support for a fragile painting by dampening vibrations due to handling, reducing the effects of shock, and minimizing the effects of varying humidity and temperature. This research evaluated the physical stability Gatorfoam imparts to a painting exposed to shock, due to accidental dropping during in-house handling, using mechanical testing. Surrogate paintings with brittle gesso coatings were subjected to corner, edge, and flat drops following ASTM drop test standards, using an affixed accelerometer, at the Canadian Conservation Institute in Ottawa. The Gatorfoam treatment provided substantial structural improvement to the paintings, and significantly protected the paintings against drop damage. The Gatorfoam provided 219% improvement in its ability to withstand impact (measured in G-force) and 329% higher drop height when dropped on its corner. The Gatorfoam provided 206% improvement in ability to withstand impact, and 203% higher drop height when dropped on its edge. Conservators can use the information obtained in this study to make a better informed decision when weighing the risks related to removing a painting from its stretcher for the purposes of structural and mechanical stabilization.
Bethany Jo Mikelait
Gatorfoam is a board of polystyrene foam laminated between two panels of proprietary resin-coated wood fibre veneer. A study was conducted to investigate the function and effectiveness of Gatorfoam in paintings conservation as a rigid, direct-contact support placed between the stretcher and the canvas. This material in theory would provide a stable physical support for a fragile painting by dampening vibrations due to handling, reducing the effects of shock, and minimizing the effects of varying humidity and temperature. This research evaluated the physical stability Gatorfoam imparts to a painting exposed to shock, due to accidental dropping during in-house handling, using mechanical testing. Surrogate paintings with brittle gesso coatings were subjected to corner, edge, and flat drops following ASTM drop test standards, using an affixed accelerometer, at the Canadian Conservation Institute in Ottawa. The Gatorfoam treatment provided substantial structural improvement to the paintings, and significantly protected the paintings against drop damage. The Gatorfoam provided 219% improvement in its ability to withstand impact (measured in G-force) and 329% higher drop height when dropped on its corner. The Gatorfoam provided 206% improvement in ability to withstand impact, and 203% higher drop height when dropped on its edge. Conservators can use the information obtained in this study to make a better informed decision when weighing the risks related to removing a painting from its stretcher for the purposes of structural and mechanical stabilization.
The Effect of Cyclododecane on Aged Acrylic Paint Films
Marie-Hélène Nadeau
This project studies the use of cyclododecane as a tool for the treatment of acrylic paint films. Cyclododecane (C12H24) is a stable molecule that sublimes and does not leave residues. It is a safe and widely used product for paper and archeological materials; it is expected that cyclododecane will also be safe for paint films. Cyclododecane has not been extensively used by painting conservators. Cyclododecane could be used as a temporary consolidant or a protection layer. The use of cyclododecane would allow conservators to perform treatments such as tear repairs, flattening and mechanical removal more safely. Of concerns was the possibility of cyclododecane leaving residues in the paint film and products migrating to the paint surface. Cyclododecane was tested on two brands of acrylic paints. Three pigments for each brand was tested. The samples used have been naturally aged to evaluate how cyclododecane affects an aged paint-film. Gloss, colour and surface tension measurements were performed on cyclododecane-coated and uncoated samples. In addition, Fourier transform-infrared spectroscopy (FT-IR) was performed in order to evaluate possible migrating products and the presence of residues.
Marie-Hélène Nadeau
This project studies the use of cyclododecane as a tool for the treatment of acrylic paint films. Cyclododecane (C12H24) is a stable molecule that sublimes and does not leave residues. It is a safe and widely used product for paper and archeological materials; it is expected that cyclododecane will also be safe for paint films. Cyclododecane has not been extensively used by painting conservators. Cyclododecane could be used as a temporary consolidant or a protection layer. The use of cyclododecane would allow conservators to perform treatments such as tear repairs, flattening and mechanical removal more safely. Of concerns was the possibility of cyclododecane leaving residues in the paint film and products migrating to the paint surface. Cyclododecane was tested on two brands of acrylic paints. Three pigments for each brand was tested. The samples used have been naturally aged to evaluate how cyclododecane affects an aged paint-film. Gloss, colour and surface tension measurements were performed on cyclododecane-coated and uncoated samples. In addition, Fourier transform-infrared spectroscopy (FT-IR) was performed in order to evaluate possible migrating products and the presence of residues.
Fill Materials and Methods for Scratch Repair on Poly(methyl methacrylate) Used in Face-Mounted Photographs
Kaslyne O’Connor
A primary conservation issue for the sustained use of face-mounted photographs is the long-term stability and inherent susceptibility of the acrylic sheet surface to abrasions. Scratches on acrylic sheet surfaces can be the result of improper handling, storage, and routine cleaning, and can range in size from micrometers to centimeters in size. The care, storage, and conservation of these acrylic face-mounted photographs have become growing subjects of debate and preservation experiments among the conservation community. A scratch on a smooth acrylic surface is composed of a trough, the depressed center, and ridges, created by the displaced acrylic material. When light is reflected by the raised ridges the scratch becomes a visual disturbance, therefore by smoothing these ridges, the visibility of the scratch should be reduced. The primary goal of this study is to determine the quality of scratch repairs for acrylic sheeting and their suitability for the conservation and preservation of face-mounted photographs. This paper examines surface modification methods (scratch-flattening and scratch-scraping) as well as fill material choice (an acrylic co-polymer, a UV-curing adhesive, and an epoxy resin displaying favourable working characteristics) in decreasing the visibility of scratches on the PMMA surface of face-mounted photographs.
Kaslyne O’Connor
A primary conservation issue for the sustained use of face-mounted photographs is the long-term stability and inherent susceptibility of the acrylic sheet surface to abrasions. Scratches on acrylic sheet surfaces can be the result of improper handling, storage, and routine cleaning, and can range in size from micrometers to centimeters in size. The care, storage, and conservation of these acrylic face-mounted photographs have become growing subjects of debate and preservation experiments among the conservation community. A scratch on a smooth acrylic surface is composed of a trough, the depressed center, and ridges, created by the displaced acrylic material. When light is reflected by the raised ridges the scratch becomes a visual disturbance, therefore by smoothing these ridges, the visibility of the scratch should be reduced. The primary goal of this study is to determine the quality of scratch repairs for acrylic sheeting and their suitability for the conservation and preservation of face-mounted photographs. This paper examines surface modification methods (scratch-flattening and scratch-scraping) as well as fill material choice (an acrylic co-polymer, a UV-curing adhesive, and an epoxy resin displaying favourable working characteristics) in decreasing the visibility of scratches on the PMMA surface of face-mounted photographs.
The Role of the Substrate in the Fading and Reversion Behaviour of Prussian Blue Dye
Sophia Zweifel
The pigment Prussian blue (ferric ferrocyanide) is known to exhibit phototropic behaviour due to its isotropic structure. Under prolonged exposure to light or in the absence of oxygen, Prussian blue will fade to Prussian white as its ferric iron is reduced to the lower oxidation state of ferrous iron. The compound will revert back to Prussian blue when re-exposed to dark, ambient conditions. However, it remains undetermined if a proteinaceous substrate might influence the reduction-oxidation reaction of Prussian blue differently than would a cellulosic substrate. This is particularly important in the case of Prussian blue dye, which was of common use on both silk and cotton textiles during the nineteenth century. This study analyses the role of the substrate in the fading and reversion of Prussian blue dye by measuring the degree and rate of Prussian blue fading and reversion across samples of different substrates (cotton and silk). The samples were exposed to light under ambient and anoxic conditions. Colour change was measured using a portable microfade tester. A second set of samples was exposed under regular and anoxic conditions in an LED light chamber at 100 klux over a twenty-day period. The colour change of these samples was measured using a portable spectrophotometer. Determining the degree and rate of colour change of Prussian blue dye on different substrates will yield significant information that could help refine more specific display guidelines
Sophia Zweifel
The pigment Prussian blue (ferric ferrocyanide) is known to exhibit phototropic behaviour due to its isotropic structure. Under prolonged exposure to light or in the absence of oxygen, Prussian blue will fade to Prussian white as its ferric iron is reduced to the lower oxidation state of ferrous iron. The compound will revert back to Prussian blue when re-exposed to dark, ambient conditions. However, it remains undetermined if a proteinaceous substrate might influence the reduction-oxidation reaction of Prussian blue differently than would a cellulosic substrate. This is particularly important in the case of Prussian blue dye, which was of common use on both silk and cotton textiles during the nineteenth century. This study analyses the role of the substrate in the fading and reversion of Prussian blue dye by measuring the degree and rate of Prussian blue fading and reversion across samples of different substrates (cotton and silk). The samples were exposed to light under ambient and anoxic conditions. Colour change was measured using a portable microfade tester. A second set of samples was exposed under regular and anoxic conditions in an LED light chamber at 100 klux over a twenty-day period. The colour change of these samples was measured using a portable spectrophotometer. Determining the degree and rate of colour change of Prussian blue dye on different substrates will yield significant information that could help refine more specific display guidelines
State University of New York College at Buffalo Master’s Program in Art Conservation
The Unfurling of Watherston’s Method: Research into the Re-Treatability of Morris Louis’s Alpha (1960)
Ellen Davis
In 1964 the Albright Knox Art Gallery in Buffalo, NY acquired Alpha (1960), by the colorfield painter, Morris Louis. The work is characteristic of Louis’s Unfurled series, with a wide expanse of bare canvas between the mirrored rivulets of color at the left and right. Being uniquely vulnerable to environmental pollutants and mishandling, condition issues requiring treatment were first noted with Alpha in 1965. Between 1977 and 1979 the conservator Margaret Watherston cleaned, sized, and re-stretched the painting on a new Lebron expansion bolt stretcher. No later than 1985 the canvas was noted as appearing significantly discolored and the artist’s signature on the canvas verso appeared to bleed through the canvas and become visible in normal light at the upper right of the canvas recto.
Both the discolored canvas and seeping signature currently proscribe the painting from exhibition and without re-treatment, Alpha’s unexhibitable condition is only expected to worsen. This research project aims to determine the feasibility of retreatment of Morris Louis’s Alpha (1960). Mock-ups were used to explore the applicability of a series of experimental re-treatment options, including overall wetting and light-bleaching and solvent reduction of the signature bleed-through.
Ellen Davis
In 1964 the Albright Knox Art Gallery in Buffalo, NY acquired Alpha (1960), by the colorfield painter, Morris Louis. The work is characteristic of Louis’s Unfurled series, with a wide expanse of bare canvas between the mirrored rivulets of color at the left and right. Being uniquely vulnerable to environmental pollutants and mishandling, condition issues requiring treatment were first noted with Alpha in 1965. Between 1977 and 1979 the conservator Margaret Watherston cleaned, sized, and re-stretched the painting on a new Lebron expansion bolt stretcher. No later than 1985 the canvas was noted as appearing significantly discolored and the artist’s signature on the canvas verso appeared to bleed through the canvas and become visible in normal light at the upper right of the canvas recto.
Both the discolored canvas and seeping signature currently proscribe the painting from exhibition and without re-treatment, Alpha’s unexhibitable condition is only expected to worsen. This research project aims to determine the feasibility of retreatment of Morris Louis’s Alpha (1960). Mock-ups were used to explore the applicability of a series of experimental re-treatment options, including overall wetting and light-bleaching and solvent reduction of the signature bleed-through.
Conservation Treatment of Early Printed Books: Possibilities, Methodologies and Outcomes
Jennifer Hunt Johnson
Development of treatment strategies for conservation is challenging when an object has undergone many campaigns of repair in its lifetime. Determining the appropriate level of intervention requires an understanding of the object’s history, coupled with achievable goals for preservation and improved function. Historia Troiana, an incunabule from 1486, and the Geneva Bible from 1597 are two books that offer an opportunity for contrasting approaches to treatment. Prior rebinding and cover to text detachment have been identified in the Historia Troiana, providing an opportunity for rebinding in full leather to restore functionality to the book and offer a more sympathetic style of binding that relates to the period of the text. In contrast, a study and minor treatment is offered to the Geneva Bible that suffers mainly from a loose gathering near the center of the text. The bible, as received, retained its initial binding. Though significantly worn, the structure was functional and provided a visual account of the history for the piece.
It is important to note the nature of the book as a commodity, as this underpins the context through which these objects have been treated throughout time. Changes in thinking in library and archives settings place greater emphasis on the physical book as a valued artifact, while digital surrogates provide alternative means to access textual information. As modern-day book conservators shift their focus from commodity to artifact, implications for treatment require new examination as well.
This presentation describes two avenues for treatment and the reasoning behind each. Questions concerning value, aesthetics, function and preservation, efficiency and skill, and historical context clash, driving towards the bigger question: what is the impact of rebinding and treatment on the use and understanding of a book? This presentation seeks to reignite conversations surrounding this issue.
Jennifer Hunt Johnson
Development of treatment strategies for conservation is challenging when an object has undergone many campaigns of repair in its lifetime. Determining the appropriate level of intervention requires an understanding of the object’s history, coupled with achievable goals for preservation and improved function. Historia Troiana, an incunabule from 1486, and the Geneva Bible from 1597 are two books that offer an opportunity for contrasting approaches to treatment. Prior rebinding and cover to text detachment have been identified in the Historia Troiana, providing an opportunity for rebinding in full leather to restore functionality to the book and offer a more sympathetic style of binding that relates to the period of the text. In contrast, a study and minor treatment is offered to the Geneva Bible that suffers mainly from a loose gathering near the center of the text. The bible, as received, retained its initial binding. Though significantly worn, the structure was functional and provided a visual account of the history for the piece.
It is important to note the nature of the book as a commodity, as this underpins the context through which these objects have been treated throughout time. Changes in thinking in library and archives settings place greater emphasis on the physical book as a valued artifact, while digital surrogates provide alternative means to access textual information. As modern-day book conservators shift their focus from commodity to artifact, implications for treatment require new examination as well.
This presentation describes two avenues for treatment and the reasoning behind each. Questions concerning value, aesthetics, function and preservation, efficiency and skill, and historical context clash, driving towards the bigger question: what is the impact of rebinding and treatment on the use and understanding of a book? This presentation seeks to reignite conversations surrounding this issue.
Acne Gel for Green Ear Syndrome? A study on copper corrosion stain removal from poly (vinyl chloride)
Dawn Wallace
The removal of copper corrosion stains within plasticized poly(vinyl chloride) are of concern to both conservators the collectors of popular vinyl dolls. Dolls such as Barbie™ and Dawn® include copper alloys as decorative elements or internal armatures which overtime may create stains within the plastic. Where the conservation field is hesitant to implement interventive treatment of plastics, public collectors are actively trying treatment methods employing common acne topical gels. Two gels were tested according to public methods to determine the removal methods of the corrosion stain, one with salicylic acid and the other benzoyl peroxide. Normal and fluorescence induced illumination documented the visible change of the samples during testing. The samples were weighed to determine possible loss of plasticizer or material. X-ray fluorescence spectroscopy (XRF) was employed to follow movement of the stain by presence of the copper αβ K-lines. It was determined the salicylic acid gel removed copper from the sample while the benzoyl peroxide acted as a bleaching agent.
Dawn Wallace
The removal of copper corrosion stains within plasticized poly(vinyl chloride) are of concern to both conservators the collectors of popular vinyl dolls. Dolls such as Barbie™ and Dawn® include copper alloys as decorative elements or internal armatures which overtime may create stains within the plastic. Where the conservation field is hesitant to implement interventive treatment of plastics, public collectors are actively trying treatment methods employing common acne topical gels. Two gels were tested according to public methods to determine the removal methods of the corrosion stain, one with salicylic acid and the other benzoyl peroxide. Normal and fluorescence induced illumination documented the visible change of the samples during testing. The samples were weighed to determine possible loss of plasticizer or material. X-ray fluorescence spectroscopy (XRF) was employed to follow movement of the stain by presence of the copper αβ K-lines. It was determined the salicylic acid gel removed copper from the sample while the benzoyl peroxide acted as a bleaching agent.
UCLA/Getty Masters Program in the Conservation of Archaeological and Ethnographic Materials
Torqua Cave: Documentation and Condition Assessment of Catalina’s Rock Images
Tom McClintock
The site of Torqua Cave is a rock shelter on Catalina Island, located 20 miles off the coast of Southern California. The largest of the Channel Islands, Catalina has a fascinating geologic history and is rich in marine and lithic resources. It was was inhabited at least 9000 years BP by the people known today as the Island Tongva. The first documentation of Torqua occurred in the early 1970’s with the identification of 19 red pictographs, although by today’s standards this campaign was not sufficiently systematic. To date there is little to no characterization of the site’s physical history.
This paper presents the results of new imaging technologies based on Decorrelation Stretch and an assessment of local climatic conditions and substrate composition, which will lead to a better understanding of the site’s history and deterioration. Following an assessment of condition, the significance of the site to its stakeholders, including the indigenous population, the island’s contemporary residents and its landowners, will be investigated.
Decorrelation Stretch is a method of producing false color digital images that is able to reveal severely faded pigmented decorative surfaces, which has been used successfully here to identify previously unrecognizable and invisible pictographs. Photogrammetry will be performed to create a unified image of the site, which, at roughly 50’ long and on a hillside, has not been possible to present previously. X-Ray Diffraction has identified the pigment used and the composition of its substrate. Portable x-Ray fluorescence (XRF) spectroscopy and ultraviolet/visible/near infrared (UV/Vis/NIR) reflectance spectroscopy will be performed on-site to create a map of the panels’ surface composition for comparison with visual characteristics such as color variation, patterns of deterioration, presence of water from various sources, and accretions. Polarized light microscopy (PLM) will be performed on a thin-section slide of the host rock’s substrate for identification of its composite minerals. Environmental data loggers will be placed at the site to measure ambient temperature (T) and relative humidity (RH) at the site through daytime/nighttime cycles for a year to compliment spot measurements of rock surface temperature, T and RH that were collected in summer 2014.
This information will be used to characterize the degradation patterns of the bedrock panels that comprise this site, focusing on the interrelationship of the rock’s composition, local climate and water transfer through the rock and from external sources. An assessment of the site’s significant and the danger of anthropogenic impact will lead to recommendations concerning future management strategies and protection.
Tom McClintock
The site of Torqua Cave is a rock shelter on Catalina Island, located 20 miles off the coast of Southern California. The largest of the Channel Islands, Catalina has a fascinating geologic history and is rich in marine and lithic resources. It was was inhabited at least 9000 years BP by the people known today as the Island Tongva. The first documentation of Torqua occurred in the early 1970’s with the identification of 19 red pictographs, although by today’s standards this campaign was not sufficiently systematic. To date there is little to no characterization of the site’s physical history.
This paper presents the results of new imaging technologies based on Decorrelation Stretch and an assessment of local climatic conditions and substrate composition, which will lead to a better understanding of the site’s history and deterioration. Following an assessment of condition, the significance of the site to its stakeholders, including the indigenous population, the island’s contemporary residents and its landowners, will be investigated.
Decorrelation Stretch is a method of producing false color digital images that is able to reveal severely faded pigmented decorative surfaces, which has been used successfully here to identify previously unrecognizable and invisible pictographs. Photogrammetry will be performed to create a unified image of the site, which, at roughly 50’ long and on a hillside, has not been possible to present previously. X-Ray Diffraction has identified the pigment used and the composition of its substrate. Portable x-Ray fluorescence (XRF) spectroscopy and ultraviolet/visible/near infrared (UV/Vis/NIR) reflectance spectroscopy will be performed on-site to create a map of the panels’ surface composition for comparison with visual characteristics such as color variation, patterns of deterioration, presence of water from various sources, and accretions. Polarized light microscopy (PLM) will be performed on a thin-section slide of the host rock’s substrate for identification of its composite minerals. Environmental data loggers will be placed at the site to measure ambient temperature (T) and relative humidity (RH) at the site through daytime/nighttime cycles for a year to compliment spot measurements of rock surface temperature, T and RH that were collected in summer 2014.
This information will be used to characterize the degradation patterns of the bedrock panels that comprise this site, focusing on the interrelationship of the rock’s composition, local climate and water transfer through the rock and from external sources. An assessment of the site’s significant and the danger of anthropogenic impact will lead to recommendations concerning future management strategies and protection.
An Analysis of Unidentified Dark Materials Between Inlaid Motifs on Andean Wooden Queros: Preliminary Findings
Heather White
Paramount in the study of Andean civilizations, past and present, are the people’s rituals and ceremonial customs which have pervaded the Inka and post-Inka periods. These rituals mark social and religious occasions with offerings to the gods that ensure economic prosperity and good health. Decorated wooden cups, called qeros, have facilitated these customs through the centuries, witnessing long use-lives as they are passed down from generation to generation. As custodians of ancient Andean rituals and ways of life, contemporary Andeans use the cups as their ancestors did: to hold and transfer libations of blood or the fermented maize beer chicha, to honor, respect, and celebrate religious, social, and economic activities. It is from here that qeros enter museum collections, their use-life ends, and their preservation as vestiges of Andean culture and ritual begins. In recent years there have been technical studies of Andean qero technology focusing on the materials used for the polychrome inlay decoration, identified as an array of natural and manufactured pigments bound by an organic resin from species of the Elagaeia tree (E. utilis and E. pastoensis), locally known as mopa mopa. However, currently there is a lack of information concerning the dark material(s) present around the polychromy, which exhibits peculiar and substantial loss on vessels in many museum collections, sometimes as though it has been physically scraped off. For this study, different dark materials surrounding the polychrome design on a group of qeros belonging to the Fowler Museum at the University of California-Los Angeles were investigated in an effort to characterize them and potentially explain the technical, cultural, and/or ethnographic reasons for their presence and causes for their loss. Various documentation and analytical techniques were employed, including visual analysis, digital photography, UV-induced visible fluorescence, Reflectance Transformation Imaging (RTI), microscopy, portable X-Ray Fluorescence (pXRF) spectroscopy, Fourier Transform Infrared (FTIR) spectroscopy, and Gas Chromatography-Mass Spectrometry (GC-MS). Preliminary results have shown surface modification and ethnographic wear which appear related to the material’s loss. Identifying this material(s), understanding its origin and explaining its loss will contribute to our knowledge of the vessels’ manufacture and/or ethnographic history and use, and guide our transferred custodianship over such artifacts of Andean traditions.
Heather White
Paramount in the study of Andean civilizations, past and present, are the people’s rituals and ceremonial customs which have pervaded the Inka and post-Inka periods. These rituals mark social and religious occasions with offerings to the gods that ensure economic prosperity and good health. Decorated wooden cups, called qeros, have facilitated these customs through the centuries, witnessing long use-lives as they are passed down from generation to generation. As custodians of ancient Andean rituals and ways of life, contemporary Andeans use the cups as their ancestors did: to hold and transfer libations of blood or the fermented maize beer chicha, to honor, respect, and celebrate religious, social, and economic activities. It is from here that qeros enter museum collections, their use-life ends, and their preservation as vestiges of Andean culture and ritual begins. In recent years there have been technical studies of Andean qero technology focusing on the materials used for the polychrome inlay decoration, identified as an array of natural and manufactured pigments bound by an organic resin from species of the Elagaeia tree (E. utilis and E. pastoensis), locally known as mopa mopa. However, currently there is a lack of information concerning the dark material(s) present around the polychromy, which exhibits peculiar and substantial loss on vessels in many museum collections, sometimes as though it has been physically scraped off. For this study, different dark materials surrounding the polychrome design on a group of qeros belonging to the Fowler Museum at the University of California-Los Angeles were investigated in an effort to characterize them and potentially explain the technical, cultural, and/or ethnographic reasons for their presence and causes for their loss. Various documentation and analytical techniques were employed, including visual analysis, digital photography, UV-induced visible fluorescence, Reflectance Transformation Imaging (RTI), microscopy, portable X-Ray Fluorescence (pXRF) spectroscopy, Fourier Transform Infrared (FTIR) spectroscopy, and Gas Chromatography-Mass Spectrometry (GC-MS). Preliminary results have shown surface modification and ethnographic wear which appear related to the material’s loss. Identifying this material(s), understanding its origin and explaining its loss will contribute to our knowledge of the vessels’ manufacture and/or ethnographic history and use, and guide our transferred custodianship over such artifacts of Andean traditions.
Technical study of a miniature Tuareg camel saddle using X-radiography and X-ray fluorescence spectroscopy
Elizabeth Anne Burr
A miniature camel saddle from the Fowler Museum is an example of the dyed leather and metal work for which the Tuareg of Niger are known. This saddle made by Hamidan Oumba for the tourist market is a replica of traditional tamzak camel saddles used by the Tuareg elite. It was suggested by an African art scholar that a miniatures such as this would be constructed using the same materials and techniques as a traditional tamzak with a wooden frame. However, X-ray imaging revealed a substrate that included more dense materials in addition to wood. X-ray fluorescence spectroscopy (XRF) data was acquired from a number of locations over different substrate materials (as corresponding to x-ray images), and different types of dyed leather, which were overlaid for interpretation. Correlations were found between the dense substrate material and the trace elements rubidium and strontium used to identify clays. This and the texture seen in X-ray image suggest that clay based components of the frame were manufactures for this object, a deviation from a traditional construction. Also, the turquoise leather was found to be rich in chlorine, copper, and tin, suggesting the use of bronze chloride corrosion to create the leather pigmentation as is traditional among the Tuareg. These results suggest a combination of both innovation and tradition in the construction of this art piece.
Elizabeth Anne Burr
A miniature camel saddle from the Fowler Museum is an example of the dyed leather and metal work for which the Tuareg of Niger are known. This saddle made by Hamidan Oumba for the tourist market is a replica of traditional tamzak camel saddles used by the Tuareg elite. It was suggested by an African art scholar that a miniatures such as this would be constructed using the same materials and techniques as a traditional tamzak with a wooden frame. However, X-ray imaging revealed a substrate that included more dense materials in addition to wood. X-ray fluorescence spectroscopy (XRF) data was acquired from a number of locations over different substrate materials (as corresponding to x-ray images), and different types of dyed leather, which were overlaid for interpretation. Correlations were found between the dense substrate material and the trace elements rubidium and strontium used to identify clays. This and the texture seen in X-ray image suggest that clay based components of the frame were manufactures for this object, a deviation from a traditional construction. Also, the turquoise leather was found to be rich in chlorine, copper, and tin, suggesting the use of bronze chloride corrosion to create the leather pigmentation as is traditional among the Tuareg. These results suggest a combination of both innovation and tradition in the construction of this art piece.
Diagnostic Imaging Techniques for the Identification of Tortoise Shell
Lesley Day
The focus of this poster is the documentation of a specific patterning, found within and unique to tortoise shell, made up of random swirling lines, which most likely correspond to the yearly depositions of keratin that occur as the turtle grows. This phenomenon has been observed in passing in some literature, but has not been fully characterized and is little understood in any discipline. The patterning has been observed as topography in some antique tortoise shell samples, and also as darkened lines in an example that appears to have suffered light damage. This poster will illustrate how documentation techniques including UV-induced visible fluorescence and Reflectance Transformation Imaging (RTI) have proven to be extremely useful in observing and documenting the pattern, and how characterization and further understanding of the pattern can be used as a diagnostic criteria for distinguishing tortoise shell from imitative materials such as plastic and horn.
The documentation illustrated in this poster is one component of my master’s thesis research about light-induced alterations to tortoise shell, and specifically how light may induce alterations to the patterning described, such as darkening and increased visibility. For the study, two taxidermied hawksbill turtles (Iretmochelys imbracata) were generously donated by the US Fish and Wildlife Department of Forensics, and the scutes from one turtle carapace were removed for use as the sample material. The samples are currently undergoing accelerated light aging under three different parameters: exposures mimicking window lighting (which filters some UV), museum lighting (which filters nearly all UV) and a chamber emitting UVA radiation. An important outcome of this research will be a better understanding of photochemically induced alterations in tortoise shell, and preventive lighting guidelines for tortoise shell materials based on the findings of the light aging study.
Lesley Day
The focus of this poster is the documentation of a specific patterning, found within and unique to tortoise shell, made up of random swirling lines, which most likely correspond to the yearly depositions of keratin that occur as the turtle grows. This phenomenon has been observed in passing in some literature, but has not been fully characterized and is little understood in any discipline. The patterning has been observed as topography in some antique tortoise shell samples, and also as darkened lines in an example that appears to have suffered light damage. This poster will illustrate how documentation techniques including UV-induced visible fluorescence and Reflectance Transformation Imaging (RTI) have proven to be extremely useful in observing and documenting the pattern, and how characterization and further understanding of the pattern can be used as a diagnostic criteria for distinguishing tortoise shell from imitative materials such as plastic and horn.
The documentation illustrated in this poster is one component of my master’s thesis research about light-induced alterations to tortoise shell, and specifically how light may induce alterations to the patterning described, such as darkening and increased visibility. For the study, two taxidermied hawksbill turtles (Iretmochelys imbracata) were generously donated by the US Fish and Wildlife Department of Forensics, and the scutes from one turtle carapace were removed for use as the sample material. The samples are currently undergoing accelerated light aging under three different parameters: exposures mimicking window lighting (which filters some UV), museum lighting (which filters nearly all UV) and a chamber emitting UVA radiation. An important outcome of this research will be a better understanding of photochemically induced alterations in tortoise shell, and preventive lighting guidelines for tortoise shell materials based on the findings of the light aging study.
Piecing together the history of an 18th century printed Armenian Prayer Scroll
Colette Khanaferov
The use of prayer scrolls along with other religious art and literature have for played a significant role in the Armenian culture since the 5th century. The scope of this study is to investigate the history and materials used on a printed, 18th century Armenian prayer scroll. This analysis involves the examination of the scroll with the use of non-destructive analytical photography, fiber optic ultraviolet-visible and near infrared reflectance spectroscopy, X-ray fluorescence and Raman spectromicroscopy. The study attempts to identify and characterize pigments, colorants, ink, and the paper used to construct the prayer scroll. The text along with the illustrations have been translated and studied in an attempt to provide an overall understanding of the scroll, printing techniques, religious significance, use, as well as the traditional practices in the Armenian culture in the 18th century.
Colette Khanaferov
The use of prayer scrolls along with other religious art and literature have for played a significant role in the Armenian culture since the 5th century. The scope of this study is to investigate the history and materials used on a printed, 18th century Armenian prayer scroll. This analysis involves the examination of the scroll with the use of non-destructive analytical photography, fiber optic ultraviolet-visible and near infrared reflectance spectroscopy, X-ray fluorescence and Raman spectromicroscopy. The study attempts to identify and characterize pigments, colorants, ink, and the paper used to construct the prayer scroll. The text along with the illustrations have been translated and studied in an attempt to provide an overall understanding of the scroll, printing techniques, religious significance, use, as well as the traditional practices in the Armenian culture in the 18th century.
Preliminary Research on Biocorrosion of Archaeological Glass
William Shelley
The scope of this research is to investigate the mechanisms and process of biologically induced corrosion of archaeological glass. Archaeological glass samples from Greece and Cyprus suspected to have undergone biocorrosion were analyzed to characterize the chemical composition, microstructure, and topography to determine the difference in the chemistry of the glass surface and the bulk. Analytical techniques included scanning electron microscopy (SEM), atomic force microscopy (AFM), and x-ray fluorescence (XRF) spectroscopy. Modern glass samples were placed in petri dishes with sulfuric and oxalic acid to simulate potential corrosion from acids produced by microorganisms. This research aims to fill a gap in our knowledge on glass biocorrosion and to evaluate the effects of microorganism on archaeological glass.
William Shelley
The scope of this research is to investigate the mechanisms and process of biologically induced corrosion of archaeological glass. Archaeological glass samples from Greece and Cyprus suspected to have undergone biocorrosion were analyzed to characterize the chemical composition, microstructure, and topography to determine the difference in the chemistry of the glass surface and the bulk. Analytical techniques included scanning electron microscopy (SEM), atomic force microscopy (AFM), and x-ray fluorescence (XRF) spectroscopy. Modern glass samples were placed in petri dishes with sulfuric and oxalic acid to simulate potential corrosion from acids produced by microorganisms. This research aims to fill a gap in our knowledge on glass biocorrosion and to evaluate the effects of microorganism on archaeological glass.
University of Pennsylvania Historic Preservation Program
Performance Assessment and Evaluation of Clear Hydrophobic and Ultraviolet Protective Treatments for Historic Log Structures
Courtney Llewellyn Magill
This research examines the durability of historical /traditional and modern synthetic clear protective treatments for historic log structures. These treatments were conducted primarily on new samples of the western species Lodgepole pine (Pinus contorta latifola), a coniferous softwood species used widely in historic construction throughout the Rocky Mountain region. After artificial weathering, the coatings were assessed primarily on their hydrophobic and UV-resistant qualities and secondarily on aesthetic appearance.
Primary testing has focused on the performance of both traditional and the newer synthetic products as measured by accelerated weathering using a QUV Panel Weatherometer. Questions considered were: Do the products significantly improve the resistance of the wood to weathering? Do the historic treatments perform at the same level as the new synthetics? Do historic and new wood samples respond to the treatments in a similar fashion or are the reactions disparate? What is the depth of penetration of these products? How are the products affected by the accelerated weathering? Is the final aesthetic appearance of the treated products “acceptable” for site presentation?
Courtney Llewellyn Magill
This research examines the durability of historical /traditional and modern synthetic clear protective treatments for historic log structures. These treatments were conducted primarily on new samples of the western species Lodgepole pine (Pinus contorta latifola), a coniferous softwood species used widely in historic construction throughout the Rocky Mountain region. After artificial weathering, the coatings were assessed primarily on their hydrophobic and UV-resistant qualities and secondarily on aesthetic appearance.
Primary testing has focused on the performance of both traditional and the newer synthetic products as measured by accelerated weathering using a QUV Panel Weatherometer. Questions considered were: Do the products significantly improve the resistance of the wood to weathering? Do the historic treatments perform at the same level as the new synthetics? Do historic and new wood samples respond to the treatments in a similar fashion or are the reactions disparate? What is the depth of penetration of these products? How are the products affected by the accelerated weathering? Is the final aesthetic appearance of the treated products “acceptable” for site presentation?
An Assessment and Evaluation on the Effects of Acidic Cleaning Methods on Unglazed Terracotta using Accelerated Weathering Test Protocols
Irene Matteini
According to the published literature, there has been limited quantitative evaluation of the short or long-term effects of the commercial cleaning of terra cotta other than visual assessment of soiling removal. Very little work (only 3% of our literature review) has attempted to measure the effects of cleaning on terra cotta by various cleaning methods. Nevertheless, 80% of all recorded terracotta cleaning relies on chemical products, the majority being acid-based.
The current research evaluates the effects of acidic cleaners on unglazed terracotta to verify the potential for damage by accelerated weathering testing. This investigation continues previous studies (Matero et. al. 1996) where findings showed that by using a 7% hydrofluoric acid-based commercial cleaning system, an increased porosity of unglazed terra cotta resulted. The questions remain whether this physical alteration will lead to accelerated weathering and material damage.
In the first phase of this research a literature review of past and current cleaning of terra cotta was completed, together with a survey of professionals involved in terra cotta restoration. In the second phase, two commercial chemical cleaners were tested in two applications on new unglazed red and tan terracotta samples: Prosoco Heavy Duty Restoration cleaner based on HF (1:3), and Prosoco EnviroKlean based on Ammonium Bi-fluoride (generally applied as a concentrate). These samples were artificially weathered based on the RILEM salt test (V.1B) and a QUV weatherometer (ASTM G154-12) and the results measured and compared for physical alteration.
Several methods of assessment were employed to evaluate the tiles before and after testing: optical microscopy, scanning electron microscopy, porosity by liquid nitrogen Immersion, color change, and texture mapping imaging. By examining physical changes and their response to accelerated weathering across two typical terra cotta clay bodies, it is hoped that better cleaning methods will be considered in practice and parameters to measure potential damage as well as cleaning efficacy become established.
Irene Matteini
According to the published literature, there has been limited quantitative evaluation of the short or long-term effects of the commercial cleaning of terra cotta other than visual assessment of soiling removal. Very little work (only 3% of our literature review) has attempted to measure the effects of cleaning on terra cotta by various cleaning methods. Nevertheless, 80% of all recorded terracotta cleaning relies on chemical products, the majority being acid-based.
The current research evaluates the effects of acidic cleaners on unglazed terracotta to verify the potential for damage by accelerated weathering testing. This investigation continues previous studies (Matero et. al. 1996) where findings showed that by using a 7% hydrofluoric acid-based commercial cleaning system, an increased porosity of unglazed terra cotta resulted. The questions remain whether this physical alteration will lead to accelerated weathering and material damage.
In the first phase of this research a literature review of past and current cleaning of terra cotta was completed, together with a survey of professionals involved in terra cotta restoration. In the second phase, two commercial chemical cleaners were tested in two applications on new unglazed red and tan terracotta samples: Prosoco Heavy Duty Restoration cleaner based on HF (1:3), and Prosoco EnviroKlean based on Ammonium Bi-fluoride (generally applied as a concentrate). These samples were artificially weathered based on the RILEM salt test (V.1B) and a QUV weatherometer (ASTM G154-12) and the results measured and compared for physical alteration.
Several methods of assessment were employed to evaluate the tiles before and after testing: optical microscopy, scanning electron microscopy, porosity by liquid nitrogen Immersion, color change, and texture mapping imaging. By examining physical changes and their response to accelerated weathering across two typical terra cotta clay bodies, it is hoped that better cleaning methods will be considered in practice and parameters to measure potential damage as well as cleaning efficacy become established.
Winterthur/University of Delaware Program in Art Conservation
Tattered Tapa: Multi-disciplinary Collaboration in the Study and Treatment of a 19th-Century Fijian Bark Cloth
Lauren Gottschlich, Anisha Gupta, Jacinta Johnson, and Alexandra Nichols
A highly degraded 19th-century Fijian bark cloth from the University of Pennsylvania Museum of Archaeology and Anthropology was studied and treated by a team of objects and paper majors in the Winterthur/University of Delaware Program in Art Conservation (WUDPAC). This collaboration provided a unique opportunity to borrow from both fields to contribute to the conservation of an object that defies the definition of object, paper, or textile. This study will contribute to the technical literature of bark cloths and demonstrate that a cooperative, interdisciplinary approach in the treatment of cultural artifacts is essential.
Previous treatment on the bark cloth, performed by objects majors in the WUDPAC Class of 2015, included surface cleaning, pressure-sensitive tape removal, and humidification. The bark cloth’s unusually deteriorated state requires an innovative approach to removing remaining pressure-sensitive tape, removing a non-original lining, and devising a strategy for consolidation and stabilization. Technical analysis aimed to answer questions regarding the object’s manufacture and condition challenges, while also informing treatment decisions. Methods included fiber identification, XRF, FTIR, and Raman. The team worked with outside experts and explored different methodologies across specialties, in particular regarding the anticipated level of intervention. As research on the topic of highly degraded bark cloths is largely unpublished, information gleaned from the treatment of this object will contribute to the current literature. This collaboration not only produced an innovative treatment approach for the bark cloth, but also had a profound impact on the team by enhancing skills in problem solving and teamwork.
Lauren Gottschlich, Anisha Gupta, Jacinta Johnson, and Alexandra Nichols
A highly degraded 19th-century Fijian bark cloth from the University of Pennsylvania Museum of Archaeology and Anthropology was studied and treated by a team of objects and paper majors in the Winterthur/University of Delaware Program in Art Conservation (WUDPAC). This collaboration provided a unique opportunity to borrow from both fields to contribute to the conservation of an object that defies the definition of object, paper, or textile. This study will contribute to the technical literature of bark cloths and demonstrate that a cooperative, interdisciplinary approach in the treatment of cultural artifacts is essential.
Previous treatment on the bark cloth, performed by objects majors in the WUDPAC Class of 2015, included surface cleaning, pressure-sensitive tape removal, and humidification. The bark cloth’s unusually deteriorated state requires an innovative approach to removing remaining pressure-sensitive tape, removing a non-original lining, and devising a strategy for consolidation and stabilization. Technical analysis aimed to answer questions regarding the object’s manufacture and condition challenges, while also informing treatment decisions. Methods included fiber identification, XRF, FTIR, and Raman. The team worked with outside experts and explored different methodologies across specialties, in particular regarding the anticipated level of intervention. As research on the topic of highly degraded bark cloths is largely unpublished, information gleaned from the treatment of this object will contribute to the current literature. This collaboration not only produced an innovative treatment approach for the bark cloth, but also had a profound impact on the team by enhancing skills in problem solving and teamwork.
Silent No More: The Material and Art Historical Analysis of an American Dummy Board
Emily Wroczynski
Silent companions or dummy boards are not necessarily rare objects, but they have not been given much attention in recent scholarship. These life-size, painted, wooden cutouts of common figures are now breaking their silence. On-going examination, instrumental analysis, and conservation treatment of a dummy board of a Turkish figure from the Germantown Historical Society at the Winterthur/ University of Delaware Program in Art Conservation are being used for a case study of the craft practice of these objects. In particular the date of manufacture has been in question and the goal of the project is to intersect material analysis with an art historical examination of primary documents, representation of costume, and painterly characteristics. Furthermore, the types of materials and preparation of the painted surface can provide clues as to the training and specialization of the craftsmen who made these objects. The previous restoration campaigns uncovered during conservation treatment also provide insight into how the significance of these objects has evolved and how subsequent stewards have interacted with dummy boards.
Emily Wroczynski
Silent companions or dummy boards are not necessarily rare objects, but they have not been given much attention in recent scholarship. These life-size, painted, wooden cutouts of common figures are now breaking their silence. On-going examination, instrumental analysis, and conservation treatment of a dummy board of a Turkish figure from the Germantown Historical Society at the Winterthur/ University of Delaware Program in Art Conservation are being used for a case study of the craft practice of these objects. In particular the date of manufacture has been in question and the goal of the project is to intersect material analysis with an art historical examination of primary documents, representation of costume, and painterly characteristics. Furthermore, the types of materials and preparation of the painted surface can provide clues as to the training and specialization of the craftsmen who made these objects. The previous restoration campaigns uncovered during conservation treatment also provide insight into how the significance of these objects has evolved and how subsequent stewards have interacted with dummy boards.
Under the Skin: Examination of an Ecuadorian Polychrome Madonna of the Immaculate Conception
Bianca Garcia
A polychrome sculpture of a Virgin of the Immaculate Conception from Quito, Ecuador of unknown maker and date was examined in an effort to help develop an appropriate treatment protocol, determine date, and understand the materials used in its construction as well as previous restorations. X-radiographs illustrated the state of deterioration of the wooden support and Fourier transform infrared spectroscopy confirmed the use of cellulose nitrate as a previous consolidant in areas of damage in the face. X-ray fluorescence suggested the use of vermillion for the areas of red in the flesh and the mantle, lithopone in the yellow of the neck of the robe, and lead white for the robe. Cross-section microscopy revealed the presence of four generations of paint layers. A layer of gilding, with paint applied directly over it, was found in the first generation in the mantle, the robe, and the moon. This is indicative of the use of the estofado polychromy technique, popular in Ecuador in the 17th century. Scanning electron microscopy coupled with energy dispersive spectroscopy corroborated the use of gold for the gilding in the first generation and revealed the use of silver leaf in the second generation, a popular technique in Quito from the 18th century on. Raman spectroscopy showed the use of Prussian blue in the fourth generation and lapis lazuli in the first generation of the blue mantle. Initially believed to be a 19th-century sculpture, it is now thought to have been made at an earlier date, possibly the 17th century.
Bianca Garcia
A polychrome sculpture of a Virgin of the Immaculate Conception from Quito, Ecuador of unknown maker and date was examined in an effort to help develop an appropriate treatment protocol, determine date, and understand the materials used in its construction as well as previous restorations. X-radiographs illustrated the state of deterioration of the wooden support and Fourier transform infrared spectroscopy confirmed the use of cellulose nitrate as a previous consolidant in areas of damage in the face. X-ray fluorescence suggested the use of vermillion for the areas of red in the flesh and the mantle, lithopone in the yellow of the neck of the robe, and lead white for the robe. Cross-section microscopy revealed the presence of four generations of paint layers. A layer of gilding, with paint applied directly over it, was found in the first generation in the mantle, the robe, and the moon. This is indicative of the use of the estofado polychromy technique, popular in Ecuador in the 17th century. Scanning electron microscopy coupled with energy dispersive spectroscopy corroborated the use of gold for the gilding in the first generation and revealed the use of silver leaf in the second generation, a popular technique in Quito from the 18th century on. Raman spectroscopy showed the use of Prussian blue in the fourth generation and lapis lazuli in the first generation of the blue mantle. Initially believed to be a 19th-century sculpture, it is now thought to have been made at an earlier date, possibly the 17th century.
Revealing Layers of Meaning: Issues in the Construction and Iconography found in a Painting Depicting the Virgin of Guadalupe
José Luis Lazarte
The study of New Spanish painting poses a series of difficulties related to authorship, lack of historic documentation, the existence of a large body of anonymous or decontextualized images, and the conservation condition governing the stylistic study of these images. This poster focuses on a painting depicting the Virgin of Guadalupe which shows a complex icon stratigraphy. The visual analysis of the construction and iconography of the painting suggests that this artwork has more in common with the traditional patterns used to create “true” devotional Guadalupean copies in Mexico. In 1751 and 1756, the Mexican painter, Miguel Cabrera, conducted a visual examination of the original image of the Virgin of Guadalupe. He noted the presence of the seam and wrote a treatise listing this feature as a necessary element for the creation of “true” Virgin of Guadalupe devotional copies. The painting showcased in this study has a seam that may be following Cabrera’s specified tradition. Ultraviolet fluorescence examination, x-radiography, cross-sectional microscopy, XRF, FTIR, SEM-EDS, Raman spectroscopy, GC-MS and, HPLC were performed in an effort to determine the time period for three distinct painting campaigns. The first layer is composed of two fragments of previously executed paintings which were seamed together to provide the current support. The second layer shows the image of the Virgin of Guadalupe and apparition scenes surrounded by a floral decorative design. The uppermost layer is an overpainting campaign which completely covers the previous composition with additional stylistic elements, such as winged angels. The information gained about the various painting campaigns will be used to instruct the treatment of the painting and further investigate layers of meaning.
José Luis Lazarte
The study of New Spanish painting poses a series of difficulties related to authorship, lack of historic documentation, the existence of a large body of anonymous or decontextualized images, and the conservation condition governing the stylistic study of these images. This poster focuses on a painting depicting the Virgin of Guadalupe which shows a complex icon stratigraphy. The visual analysis of the construction and iconography of the painting suggests that this artwork has more in common with the traditional patterns used to create “true” devotional Guadalupean copies in Mexico. In 1751 and 1756, the Mexican painter, Miguel Cabrera, conducted a visual examination of the original image of the Virgin of Guadalupe. He noted the presence of the seam and wrote a treatise listing this feature as a necessary element for the creation of “true” Virgin of Guadalupe devotional copies. The painting showcased in this study has a seam that may be following Cabrera’s specified tradition. Ultraviolet fluorescence examination, x-radiography, cross-sectional microscopy, XRF, FTIR, SEM-EDS, Raman spectroscopy, GC-MS and, HPLC were performed in an effort to determine the time period for three distinct painting campaigns. The first layer is composed of two fragments of previously executed paintings which were seamed together to provide the current support. The second layer shows the image of the Virgin of Guadalupe and apparition scenes surrounded by a floral decorative design. The uppermost layer is an overpainting campaign which completely covers the previous composition with additional stylistic elements, such as winged angels. The information gained about the various painting campaigns will be used to instruct the treatment of the painting and further investigate layers of meaning.