Second-Year Research Project, 2010-11
The Rupture of Mont St. Hilaire: Instrumental Analysis to Discover the Causes of Deterioration
Tasia M. Bulger
In 1971, Watson Hall, Queen's University, commissioned Jordi Bonet, a prominent Canadian artist from Montreal, to create a sculpture of packed Styrofoam®, fiberglass coated with epoxy, acrylic paint, and lacquer. The sculpture produced was Mont St. Hilaire, an abstract representation of St. Hilaire Mountain, in Quebec. The sculpture remained outdoors on the Queen's campus for 22 years, exposed to all weathers, until it was acquired by the Agnes Etherington Art Centre (AEAC) and relocated indoors. The deteriorated state of the sculpture became quickly apparent: the lower right corner of the fiberglass coating had cracked and fallen away, exposing the inner foam core of the sculpture. A thorough analysis of the material composition of the fiberglass, coatings, and foam core will be completed using Fourier transform infrared (FTIR) spectroscopy, optical light microscopy, and visual examination. Establishing the exact composition of the materials used will allow the solubility of the materials to be determined for eventual treatment. Discovering which factors caused the sculpture to deteriorate and developing a conservation treatment proposal and maintenance plan for the AEAC to consider are the goals of this research. It is anticipated that the investigation will determine the foam core to be composed of open-celled foam which suffered water penetration at an unseen area of fracture, thereby causing major damage on the right side of the sculpture.
Quantifying Silver Cleaning Techniques Using Non-Contact, Three-Dimensional White Light Profilometry
Previous studies evaluating different tarnish removal (polishing) techniques on historic silver have used measurements of cleaned samples obtained from scanning electron microscopy (SEM). SEM investigations of roughness have been limited by: sample preparation, the small field of view, difficulty of extracting depth information from two-dimensional (2D) images, and limited sample size. In contrast, white light profilometry provides extremely accurate three-dimensional (3D) measurements detecting surface changes as small as three nanometers in depth. Much larger surface areas are able to be scanned than with SEM, thus generating more accurate roughness statistics. This experiment compared the effects of six different silver polishes employing a white light profilometer. The readings for surface roughness and scratch depths were compared. Profilometry will put the evaluation of the silver cleaning techniques most often used by conservators on a firm quantitative ground. The results will be offered as a practical conservation guide for silver cleaning or polishing regimes.
Analysis of the Physical Characteristics of Transparent Cellulosic Nanofiber Paper
Transparent or oversized works of art on paper are often difficult to exhibit because traditional tissue hinges can be visible through the media or are not strong enough to support the work adequately. Due to aesthetic and conceptual considerations, contemporary works of art on paper are often exhibited unframed, leaving little or no margin for use of traditional hinging techniques. The following research analyses the physical characteristics of transparent nanofiber paper as an alternative hinging material for transparent or oversized works of art. For comparative analysis, a Kozo Japanese tissue was exposed to the same test parameters as the nanofiber paper. The objective of the research was to determine the physical and chemical stability of the nanofiber paper when exposed to ultraviolet and thermal accelerated aging. Instrumental analysis determined the following physical characteristics, before and after aging: colour using the tri-stimulus L*a*b* system, yellowness, brightness, pH, zero-span tensile strength, sorption properties, and moisture content. Samples were viewed using scanning electron microscopy to examine their topographic microstructure and to determine fiber size and distribution. Fourier transform infrared spectroscopy was used to determine the elemental composition of each sample and the degree of polymerization was calculated from intrinsic viscosity data with cupriethylenediamine as the solvent. Sample analysis indicated that the transparent nanofiber paper exhibited physical characteristics similar to both paper and plastic materials. This research presents a range of instrumental, compositional, and topographical imaging data that will contribute to the current published literature related to the research and development of cellulosic nanofiber materials and their possible use within the field of art conservation.
A Study of Varnish Coatings for Contemporary Murals in Canada
The effectiveness of commercially available varnish coatings will be tested in terms of how well they protect outdoor murals against deterioration. The focus will be on varnishes that are used specifically for outdoor, contemporary, acrylic murals in Canada. The causes of deterioration of murals are many, but this project will examine only deterioration caused by weather conditions. The coatings will be tested on two different types of support: a wood panel rigid support and a clay brick rigid support, both of which will be primed with a latex ground. The three varnishes to be tested are currently being used by working mural artists and are recommended by mural associations. In addition, there will be a sample that has only the paint layer with no coating, and a control sample, where the varnish has been brushed on to a piece of glass. The former sample will serve as an interesting comparison with the varnished samples, as many muralists do not apply any coating at all to their work. The samples will be exposed to a combination of ultraviolet light, fluctuating temperature, and fluctuating relative humidity for a period of 28 to 56 days. The testing methods will investigate texture, colour, and gloss changes. The samples may also be tested for brittleness after accelerated aging. It is hypothesized that the polyurethane varnish will withstand the experimental conditions the best, due to the polyurethane's long molecular structure and versatility as a commercially viable outdoor sealant; however, this varnish may also prove to be the most difficult to remove.
The Performance of Two Commercial Anti-Graffiti Coatings, PSS 20 and Faceal-Oleo HD for Historic Limestone Buildings
This project will assess the ability of two commercial products to prevent graffiti staining on Kingston limestone. The performance of PSS 20, a sacrificial polysaccharide-based coating, and Faceal-Oleo HD, a permanent anti-graffiti coating with a fluorinated acrylic copolymer in the aqueous phase, will be evaluated to determine their suitability as conservation materials. Samples preconditioned at 20°C and 45% relative humidity (RH) for a 14-day period will be naturally aged on weathering racks. Some samples will be exposed to ultraviolet (UV) radiation. Samples will then be tested for hardness, resistance to abrasion that occurs as a result of cleaning, and colour and gloss changes. Fourier transform infrared spectroscopy with an attenuated total reflection attachment (FTIR-ATR) will be used to determine possible changes in the chemical structure of the coating as result of ageing. Water absorption will be measured using the absorbency test method developed by the Réunion Internationale des Laboratoires et Experts des Matériaux, systèmes de construction et ouvrages (RILEM). The anti-graffiti coatings will be applied using two methods, manual brushing and spraying. The graffiti material will be a polyurethane spray paint, a lacquer spray paint, a solvent-based ink marker, a water-based ink marker, and a wax crayon in accordance with the Standard Practice for Determination of Graffiti Resistance (ASTM-D6578-08). Both coatings are expected to change appearance after exposure to UV radiation and natural ageing with an increase in yellow and in gloss. The cleaning required to remove coatings will probably cause less damage to the PSS 20 than the Faceal-Oleo HD. The water absorbency of the limestone should be reduced by the application of a coating. Finally, both products are expected to completely block the graffiti material from reaching and staining the stone surface.
An Investigation of Suitability of Aquazol®-Based Filler Materials
The polymer poly(2-ethyl-2-oxazoline) commercially known as Aquazol® is becoming a commonly employed adhesive in art conservation. There are many references in the conservation literature to use of this adhesive as a consolidant and, recently, as an in-painting binder. The aim of this study is to explore Aquazol's suitability as a binder when dissolved in water and mixed with calcium carbonate as an inert material, for producing stable fills for paintings on fabric supports. The focus will be on the 200 and 500 grades of this resin, two of the highest molecular weight grades of Aquazol® currently available through its manufacturing company Polymer Chemistry Innovations, Inc. Experimental tests will include tensile testing to determine the strength and stiffness of the fillers. In addition, tests of other characteristics, such as handling, reversibility, shrinkage, flexibility, chemical degradation using gel permeation chromatography, and colour stability will also be conducted. The test results obtained from Aquazol® fillers will be compared with the traditional, well-established standard filler, rabbit skin glue and chalk-filler, still used in conservation.
The Alteration of Different Types of Mercuric Sulphide Pigments under Light
Emmanuelle A. Perron
This research compares alterations of different types of historically used red mercuric sulphide pigments when exposed to different sources of lighting and in the presence of sodium chloride. The use of natural cinnabar or mercuric sulphide as a pigment can be traced back to prehistory and such use spread from China to Europe until the development of the artificial dry-processed vermilion in the 8th century and the "modern" wet-processed vermilion in the 17th century. Nevertheless, the use of all three types of mercuric sulphide pigments in easel and wall paintings has resulted in darkening in patches. The presence of light, particularly in the wavelengths of 400-570 nm, and the presence of various impurities, especially chlorine, have been identified as the main cause of the darkening of these pigments. In this research, cinnabar and vermilion pigments were mixed with cold-pressed linseed oil and painted on Masonite boards. They were left to dry for six weeks in the dark. Then, one set was placed into the Q-sun Light Accelerated Ageing instrument, another set was placed under high output fluorescent lights, another was carried to the Canadian Conservation Institute to use their microfader instrument, and the last set was left in the dark throughout the experiment to serve as a control. During this period, a portion of the samples were sprayed with distilled water with or without sodium chloride. The colour alterations of these paint samples were recorded with a Minolta colorimeter using the CIELAB L*a*b* System. In addition, the composition of the dry-processed pigments was analyzed with the use of the optical microscope and x-ray fluorescence (XRF). According to the literature, the addition of sodium chloride followed by light exposure should result in the darkening of all mercury sulphide pigments, regardless of their manufacturing process and initial levels of purity.
The Effect of Ozone on Cellulose Strength: Considering Ozone for the Removal of Odour from Paper Artifacts
Ozone gas can be used to remove odour and is particularly effective for removing smoke and musty smells from books. Disaster remediation companies commonly use this treatment to remove odour from artifacts. The process, however, involves the uncontrolled release of highly reactive ozone molecules into the vicinity of the object; these molecules deactivate the particles causing odour, but are also likely to oxidize materials in the artifact, resulting in deterioration. The goal of this project is to investigate how the structure of cellulose is affected when paper is exposed to ozone in high but brief doses. Samples of Whatman filter paper will be used for the tests, and the change in cellulose strength will be measured by determining the copper number of the paper, a measure which indicates deterioration levels, before and after ozone exposure. The paper samples will be exposed to ozone gas at a concentration and duration comparable to that used in the restoration industry, and a second time in conditions exceeding normal treatment levels. A separate sample will be bleached with hydrogen peroxide, a treatment also known to cause oxidation of cellulose but considered acceptable when weighed against the improvement to the artifact; the copper number of this sample will be determined and compared with the ozone- treated papers. It is hoped that this research will establish the amount of deterioration cellulose suffers when exposed to ozone for the purpose of eliminating odour, and provide some insight into the risks associated with this treatment.
Comparing X-ray Computed Tomography Images of Corroded Coins with Results from Traditional Cleaning
Traditional methods of cleaning corroded metal artifacts involve the physical removal of corrosion products, a process that can cause damage to the highly mineralized original surface. X-ray computed tomography (XCT) was used to study Greco-Roman coins from the Diniacopoulos Collection at Queen's University, a collection jointly held by the Art Conservation Program and Department of Classics. A CT scan is conducted by acquiring a series of two-dimensional x-ray projection images captured at different rotation angles. This study used an Xradia MicroXCT-400 x-ray CT scanner in conjunction with various reconstruction and visualization software packages. As several coins were identified from the XCT scans, it was determined that the next step in the conservation aspect of this project would be to compare the results from the XCT scans with results from traditional cleaning. Mechanical cleaning will be used to reduce corrosion product on the Diniacopoulos coins, which have already been imaged by XCT. Additionally, sample coins were prepared by the Mechanical Engineering Department, using three different coppery-alloys. The coins will be artificially corroded and then imaged using XCT, after which they will be mechanically cleaned. The cleaned Diniacopoulos coins and the sample coins will be photographed using both normal digital photography and reflectance transformation imaging (RTI). These photographs will then be compared to the XCT scans. It is believed that the x-ray CT images will be clearer than the results from traditional cleaning as it is not always possible to uncover any raised features while cleaning.
The Long-Term Effects of Mounting Digital Ink Jet Prints to Aluminum and Dibond® Supports
The long-term effects of mounting digital ink jet prints to aluminum and DibondÒ supports were determined. Digital ink jet prints, particularly large format works, are commonly mounted to rigid supports, such as Dibond® and aluminum, to provide structural support for the prints. DibondÒ is a composite material consisting of two thin aluminum sheets bound by a polyethylene core. Two different printing papers were used for the digital ink jet prints to reflect the variety available to contemporary artists. The papers selected were Epson Premium Lustre Photo Paper, an RC (Resin Coated) paper, and Epson Velvet Fine Art Paper, a 100% cotton rag paper. Further, the appropriate ink and paper combinations were chosen to ensure that the longevity of the digital ink jet prints was not compromised. Although the individual materials used for the mounting process were inherently stable, they have different coefficients of thermal expansion. The mounted samples underwent thermal accelerated aging in a vacuum oven. With the materials interacting continuously over time, it was hypothesized that the mounted digital ink jet prints would degrade at an increased rate. The mounted samples were compared to a control set of un-mounted samples. Prior to the accelerated aging process, reflectance transformation imaging (RTI) was used to determine the initial surface characteristics of the samples. Further, the samples were also viewed and imaged using a reflectance microscope prior to and after accelerated aging in order to observe if any changes to the printing inks had occurred. It was anticipated that the results of this research project would indicate that the mounting of digital ink jet prints to aluminum and DibondÒ will inevitably cause an increase to the amount of degradation visible on the surface of the prints as a result of the mounting process.
Second-Year Research Projects, 2007-08
The Effect of Deacidification Solutions on Unstable Watercolour Pigments
The degradation and subsequent stabilization of paper through deacidification treatments has been well studied. Less is known about the effect of these treatments on works of art on paper, in particular on works using watercolour paint. Four unstable pigments will be examined for changes to colour and pH after treatment with four deacidification solutions. Indigo, carmine, and gamboge, pigments that fade rapidly in light, and Prussian blue, which is very pH sensitive, will be sprayed with aqueous solutions of calcium hydroxide, calcium bicarbonate, and magnesium bicarbonate. Samples will also be treated with the solvent-based Wei'To solution for comparison purposes. Cold extraction pH tests and colour changes monitored with a colorimeter will be taken from samples at pre-treatment, pre-aging, and post-aging stages of the experiment. Samples will be deacidified from the verso, as in regular treatment, and from the recto, for a more direct monitoring of interaction between solution and paint. Ready-made colours by Winsor & Newton will be painted on to sized paper with 100% cotton fibre content. Half of the samples will be subjected to dark ageing for three months, while the other half will undergo accelerated ageing for a period of 144 hours at 50ºC, equal to 25 years. A set of samples will be kept for future testing of long-term natural ageing. The results of the experiment are expected to establish which solution best safeguards both the aesthetics and permanency of the image.
Paper Extract Compared with Traditional Toning Materials
A toning material, 'paper extract', will be compared with traditional toning materials used by conservators to tone a repair prior to its application or in order to integrate a completed fill with the original material. Although paper extract has been mentioned in some literature as an appropriate toning material, it has not been extensively studied. Paper extract is made by boiling down the wash water from aged paper scraps. Two batches of paper extract will be made, the first will be prepared with distilled water and the second with water alkalized with Ca(OH)2 to a pH of approximately 8. A sample of the extract will then be analysed with gas chromatography mass spectroscopy (GC-MS) and Fourier transform infrared spectroscopy (FTIR) to determine the major constituents. The sample is expected to consist of monosaccharides as well as carboxyl functional groups. The pH of each sample will be determined before and after accelerated ageing using cold extraction and measuring with an electronic pH meter. The extract samples will then be applied to an appropriate paper and aged artificially together with samples of paper toned with tea, raw umber acrylic paint, and Vandyke brown watercolour. These pigments were chosen because they are rated as very permanent by the ASTM group. Ageing will be carried out in a temperature and relative humidity chamber in order to test the stability of the paper after exposure to the toning materials. Another sample set will be light aged to determine the degree to which the materials are fugitive to light. The effect of the accelerated aging will be recorded using colorimeter readings made before and after ageing. The stability of the paper will be measured using the M.I.T. fold-endurance tester according to TAPPI standards. This study has two objectives. The first is to evaluate the appropriateness of paper extract as a toning material in conservation and the second is to assist conservators in making decisions about which toning materials to use.
The Effects of Butvar B-98 on Bronze
Butvar B-98, a polyvinyl butyral resin used in conservation, is known to be an effective consolidant for dry wooden objects; however, its effect on metals is not yet fully understood. In the early 1990's, conservators' treatment of a composite wood and bronze serving stand at the Gordion Furniture Project in Turkey prompted the testing of a variety of materials to determine the best wood consolidant and coating for the bronze studs on the stand. While testing indicated that Butvar B-98 may increase the rate of corrosion on the bronze studs, it was determined to be the most appropriate consolidant for the wood. The wooden fragments of the stand were therefore immersed in a 10% w/v solution of Butvar in 60:40 ethanol/toluene up to the level of the studs, which were cleaned and coated instead with Acryloid B-72. The possible interactions between Butvar B-98 and the bronze studs, which are relatively close on the serving stand, have never been fully investigated. In order to resolve this issue, in this research bronze coupons will be coated with Butvar B-98 and tested under a variety of environmental conditions. Uncoated and coated coupons will be placed in a chamber with ideal relative humidity (RH) and temperature, a chamber with high RH, a chamber with high temperature, and a chamber with an acidic atmosphere. The coupons will be monitored for the development of corrosion both visually and by reflected light microscopy. Weight changes will be recorded and corrosion product, if detected, will be analyzed by x-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). In addition, pH testing and a modified Oddy test will be performed using dried films of Butvar B-98. It is hoped that this research will clarify whether Butvar B-98 induces corrosion on bronze objects, and if so, under what environmental conditions.
Painting Lining Process and the Effects of Pre-Tensioning
The purpose of this study is to investigate the lateral movement of lining fabric during the lining process, and the effects of pre-tensioning fabric. With the advent of new "rigid" fabrics, the process of pre-tensioning lining fabrics has in some cases been replaced by the process of lining paintings on to loose fabric. For this reason this study will focus on the effects of pre-tensioning on different polyester fabrics. Samples will be prepared using three different lining fabrics: medium weight Dacron polyester, polyester sailcloth and linen-look polyester fabric. In order to compare the results of several preparation methods, the lining fabrics will be subjected to controlled levels of tension as a percentage of the dimension, ranging from no tension, to a high level of tension. Both pre-tensioned and loose fabrics will be coated with BEVA 371. In order to monitor the movement of the fabric, a flexible but dimensionally stable film will be adhered to the fabrics, under typical vacuum lining conditions. Movement of the lining fabric relative to the film layer will be measured by curvature of the samples after they have been released from the vacuum. Thus, it is the rebound of the lining after exposure to heat and pressure that will be examined. A control sample will be prepared using two pieces of stable film laminated under vacuum using BEVA 371. Using both weave geometry and curvature formulas, some results will be predicted mathematically. A micrometer will record any change in the thickness of the fabric before and after lining. Gaining a better understanding of the movement of fabric during a typical lining will aid in choosing lining materials and preparation techniques, and may shed light on the dynamics of woven fabrics.
Diaminoalkanes as Swelling Inhibitors in Limestone Conservation
Limestone sculptures from Nega el-Deir exhibit ongoing deterioration during their storage in museum environment. Work by Rodrigez-Navarro et al. in 1997 demonstrated the deteriorative effects of sepiolite and palygorskite in the stone. Cyclic expansion and contraction of the clays caused fracture and disintegration; cycles of relative humidity caused spalling and delamination of the stone surface. Application of diaminoalkane surfactants as a protective measure shows up to 50% reduction in swelling in sandstone in a lab situation. The objective of this research is to examine the protective effects of diaminoalkanes on clay-bearing Egyptian limestone and to identify any drawbacks with this treatment. Two main concerns connected with treating the Egyptian limestone with diaminoalkanes are: the use of water as a carrier for the surfactant and the formation of residual salts as a result of the treatment. Four systems will be tested on samples made of a mixture of proportional sepiolite and palygorskite as preliminary tests: 1,4 diaminobutane in water; 1,4 diaminobutane in ethanol with the addition of acetic acid; 1,4 diaminobutane dihydrochloride in water; and 1,4 diaminobutane dihydrochloride in ethanol. The system that displays the best outcomes with respect to reduction in swelling and the formation of residual salts, will be tested on limestone samples from a Nega el-Deir sculpture. The effectiveness of the diaminoalkane in reducing swelling will be evaluated by exposing treated and untreated samples to 100% relative humidity and comparing the changes in size. Treated and untreated samples will also be subjected to RH cycles in order to evaluate the effectiveness of the treatment in reducing damage caused by cyclic expansion and contraction of the clays. Formation of salts on the stone samples as a result of the treatment will be evaluated using x-ray diffraction. It is hoped that by applying diaminoalkane as a swelling inhibitor, the delamination, spalling and even fracture of the stone caused by the clays can at least be reduced, if not eliminated.
An Investigation into the Effects between Copper Supports and Various Pigments
The objective of this research is to gain a better understanding of the behaviour of four pigments used in the sixteenth to eighteenth centuries with variously prepared copper supports and under different conditions. Oil painting on copper supports is thought to have originated in sixteenth -century Italy and remained popular until the middle of the eighteenth century. Artists from the Netherlands learnt about the technique in Italy and spread the knowledge of it during their travels though other parts of Europe. Some oil paintings on copper have survived in excellent condition, whereas others have endured severe deterioration. This project will observe whether different pigments containing varying components such as copper and mercury react in different ways to the copper substrate. The research will also look at whether the presence of the ground layer changes the behaviour of the the paint layer . As well, the project will identify any corrosion between the paint layer and copper support in order to determine if there are any differences in the composition of the corrosion between the different materials. Samples will be made using traditional methods and will be examined visually before and after aging and exposure to high relative humidity. Cross-sections will be made and analyzed using both polarized light microscopy and scanning electron microscopy. Any corrosion products will be identified using x-ray diffraction (XRD) and the paint layer will be analyzed using Fourier transform infrared spectrometer (FTIR). It is hoped that the results obtained will help to provide a better understanding of the interactions between the paint layer and the copper support.
Interactions between Metal Components and Poly(vinyl chloride) Textiles in the Preservation of 20th-Century Material Culture
Poly(vinyl chloride) (PVC) textiles were widely adopted in the 20th century for automobile and furniture upholstery, and wearable garments and accessories. Research has found that PVC materials are degrading quickly and the release of acidic vapours from solid PVC-based artifacts has been found to initiate the corrosion of metal components attached to or near the PVC artifacts. Additionally, it has been found that metal corrosion products have transferred to and discoloured some PVC artifacts. In the case of upholstery and wearable PVC, metal-anchoring devices and embellishments may be at risk from the vapours released by the PVC textiles as they degrade. The long-term effects of associations between metals and PVC have received limited study, and in the context of PVC textiles, almost none. This project will aim to characterize the interaction between brass, a typical upholstery and decorative metal, and two types of PVC textiles during ageing with and without the metal corrosion inhibitor Agateen lacquer No. 27 which, it is hoped, may protect against acidic PVC degradation vapours. Thermal and light ageing of the samples will be undertaken with and without the corrosion-inhibitor coating, and a variety of visual observations and advanced methods of analysis will be undertaken to interpret and compare results. A colourimeter and glossmeter will track changes in the colour and gloss of the PVC textiles as they age, and analysis of corrosion products on the metal and PVC samples will be made with X-ray diffraction (XRD). Scanning electron microscopy (SEM) will be used before and after ageing to interpret the morphological effects of the acidic vapours and corrosion products on the samples, thereby leading to a greater understanding of how PVC and metals interact over time.
Effects of Exposing Synthetic Acrylic Emulsion Paints to Acetic Acid Vapours
Stan Brakhage, one of the most influential cinematographers of modern times, produced completely non-narrative and abstract films by hand-painting with translucent acrylics on transparent motion picture films, frame by frame. Studies of the degradation of cellulose acetate films have shown that such films release acetic acid upon degradation, in what is commonly known as the "vinegar syndrome". A study of the effects of exposing synthetic acrylic emulsion paints to acetic acid will be carried out. Three paints of different color but similar binder will be mounted on glass slides and exposed to acetic acid vapours in two concentrations, a diluted solution and a concentrated solution. After exposure, samples will be thermally aged for a period of two weeks in aging chambers set to two different temperatures, room temperature and a higher temperature. The composition of the acrylic paint films will be studied using Fourier transform infrared spectroscopy (FTIR) before exposure, after immediate exposure to the acid and after aging. FTIR spectra will be compared to determine any change caused by the vapours in functional groups in the paint media. In addition, samples will be studied using pyrolysis-gas chromatography-mass spectroscopy (Py-GC/MS). Visual changes will also be monitored. It is expected that the acetic acid vapours will cause a slight change in the composition of the acrylic polymers. Changes in functional groups will be observed in the IR spectra. It is expected that changes will be most noticeable on the samples that were exposed to more concentrated acetic acid vapours and that were aged in the hot environment.
Enzyme, Bleaching, & Solvent Treatments Used to Remove Artificially Aged Linseed Oil from Two Types of Paper
Cher L. Schneider
This research project will evaluate the effectiveness of three conservation treatments for the removal of linseed oil stains from a cotton fiber and polyester fiber paper. These two types of papers represent real artworks: Andy Warhol's Mao and Donald Judd's Untitled. Both series of prints are located at the National Gallery of Canada in the Prints and Drawings collection. The Gallery has multiple copies of each print, all of which have oil stains leached from the dried paint layer to the paper substrate causing visual disruption to the original image. Mohawk Radiance Expression and Yupo will be used for the paper substrates in this experiment. Stand oil (polymerized linseed oil) will be placed on to the chosen paper and then artificially aged to approximate the real ages of the Warhol and Judd prints. A series of treatments, including enzyme (lipase), bleaching, and solvent treatments, will be conducted to reduce or remove the oil stains from each sample. Pretesting will be done on bleaches and solvents to identify the best and least volatile for the actual treatments. Data will be collected before and after each treatment. The analysis will include: color measurements, microscopy on the fibers, photo documentation, image analysis, paper strength, scanning electron microscopy (SEM), and Fourier transform infrared spectroscopy (FTIR).
Dry Light Bleaching: Removal of Porous Point Pen Stains on Paper
The proposed research project involves the bleaching of porous point pen stains on paper objects using a non-aqueous light bleaching treatment. A preliminary experiment was conducted on eight Crayola Washable Markers applied to a single sheet of bond paper. The sample was exposed to fluorescent light for a total of 749 hours and the degree of fading was visually observed at the end of the exposure time. It was observed that the coloured inks faded at different rates and intensities, for example, the blue ink faded considerably whereas the yellow faded very little. In the present study, samples of red, blue, and green porous point pen inks made by different companies will be applied to Whatman filter paper and subjected to fluorescent light over a three-week period of time. Although the dye particles are expected to fade, the fading characteristics of the individual inks are unknown. Colour change will be monitored with a colorimeter before light bleaching, after light bleaching, and after aging. A selection of the samples will be treated with Wei T'o, a non-aqueous deacidifying solution, prior to bleaching while the remaining samples will not be treated. The samples will be thermally aged for two weeks after which a series of tests will be carried out to determine the strength, pH, and degree of polymerization of the samples. It is hoped that the damage to the paper fibres will be minimal as a result of the use of the Wei T'o deacidifying solution.