Stephen Hackney (2016) Colour measurement of acid-detector strips for the quantification of volat... more Stephen Hackney (2016) Colour measurement of acid-detector strips for the quantification of volatile organic acids in storage conditions, Studies in Conservation, 61:sup1, 55-69, Acid-detector (A-D) strips were originally developed to assess the deterioration of acetate film stock, but they can also be used more generally within enclosures to detect volatile acidic pollution. A hand-held reflectance spectrophotometer was used to record the colour of individual strips in order to make consistent and reproducible readings. Calibration was carried out using the yellow-blue axis b*(D65) value in the CIELAB1976 system to measure the colour of A-D strips suspended in enclosed containers over solutions of acetic acid in combinations with glycerol to control the relative humidity (RH). A-D strips were found to be sensitive to changes in high RH (60-90%) but affected little by changes in lower RH or temperatures in the museum display and storage range. A-D strips can be used to establish the presence of volatile acids, record the indication of acid vapour concentration, explore conditions within a container, and to find sources of volatile acidity. They respond very quickly and several can be placed around an object. They therefore show promise for measuring slowly changing conditions, such as seasonal changes and the gradual accumulation of acidity in poorly ventilated containers and spaces. A-D strips proved useful in assessing air quality in storage and display enclosures. Examples and test results are presented. Wellsealed plywood transit frames and storage cases were found to be most polluted with volatile acids. Storage rooms with air filtration systems but filled with wooden objects had significantly reduced air quality.
Abstract: Examines the removal of dirt from some of Turner's unvarnished oil paintings: the ... more Abstract: Examines the removal of dirt from some of Turner's unvarnished oil paintings: the nature of the dirt on his unfinished paintings-greasy particles, smoke, sulphur dioxide; the adhesion of dirt-birding, absorption, etc.; cleaning-application on cotton wool swabs of ...
Speckle interferometry techniques with their high resolution full-field measurement capability of... more Speckle interferometry techniques with their high resolution full-field measurement capability offer a means of investigating the complex stress-strain behaviour of art objects under relatively low loading conditions. The focus of this paper is the investigation of art samples using the optical techniques of shearography and digital holography. A typical icon construction is a number of layers of egg tempera paint, gold paint and grounding on a wooden base. Oil paintings on canvas are typically composed of a number of layers of priming and oil paint on a canvas, with the canvas tension controlled by the stretcher. In both cases there is an opportunity for a complex stress field to develop as the canvas or wood expands or contracts at different rates to the paint and priming layers under changes in humidity and temperature. Shearography is a full-field optical technique, employing a common path shearing interferometer, which is sensitive to the displacement gradient. Digital holograp...
Shearography is a full-field optical technique usually used for non-destructive testing and for t... more Shearography is a full-field optical technique usually used for non-destructive testing and for the measurement of surface strains. This work is the development of a novel Impact Assessment Procedure (IAP), using shearography to collect the data about the condition of the artwork. This is a multi-step process with the first step being the recording of reference phase maps and the determination of signature features (anomalies in the phase map profile). After the artwork has undergone an impact which could possibly change its condition (e.g. transportation, malicious damage, conservation, aging) it is re-measured and the data is compared with the reference. The information obtained can be used by conservators to guide future conservation strategies on the artwork. This manuscript describes the development of a custom shearography prototype sensor for this purpose and the development of the IAP with a measurement programme on canvas and wooden panel painting samples.
Controlling Light with Light: Photorefractive Effects, Photosensitivity, Fiber Gratings, Photonic Materials and More, 2007
... 1Cédric Thizy, 1Marc P. Georges, 2Eleni Kouloumpi, 3Tim Green, 3Stephen Hackney,4Vivi Tornari... more ... 1Cédric Thizy, 1Marc P. Georges, 2Eleni Kouloumpi, 3Tim Green, 3Stephen Hackney,4Vivi Tornari 1 Centre Spatial de Liège Université de Liège, Liège Science Park, B-4031 Angleur, Belgium ... Two types of artwork are considered : wooden icons and textile canvas paintings. ...
O3A: Optics for Arts, Architecture, and Archaeology, 2007
This paper is one of a series submitted by the Multi-Encode Project consortium and covers the dev... more This paper is one of a series submitted by the Multi-Encode Project consortium and covers the development of holographic interferometry with dynamic photorefractive crystals. The aim of the first phase of the project is to assess the existing techniques for detection of signatures in various types of artworks. The trademark of our technique is a very high resolution in the fringe pattern. We will show the potentiality of our technique for the present application.
O3A: Optics for Arts, Architecture, and Archaeology, 2007
This is one of a series of papers submitted by the Multi-Encode Project consortium (006427 (SSPI)... more This is one of a series of papers submitted by the Multi-Encode Project consortium (006427 (SSPI)). Shearography, a full-field speckle interferometry technique, is applied to the investigation of movable cultural heritage. For this project a portable shearography sensor was ...
O3A: Optics for Arts, Architecture, and Archaeology, 2007
The design and experimental method for the use of a novel instrument for lightfastness measuremen... more The design and experimental method for the use of a novel instrument for lightfastness measurements on artwork is presented. The new microfadometer design offers increased durability and portability over the previous, published design, broadening the scope of locations at which data can be acquired. This reduces the need for art handling or transportation in order to gain evidence-based risk assessments for the display of light-sensitive artworks. The instrument focuses a stabilized high powered xenon lamp to a spot 0.25 millimeters (FWHM) while simultaneously monitoring color change. This makes it possible to identify pigments and determine the lightfastness of materials effectively and non-destructively. With 2.59mW or 0.82 lumens (1.7 x10 7 lux for a 0.25mm focused spot) the instrument is capable of fading Blue Wool 1 to a measured 11 ∆E ab value (using CIE standard illuminant D65) in 15 minutes. The temperature increase created by focused radiation was measured to be 3 to 4°C above room temperature. The system was stable within 0.12 ∆E ab over 1 hour and 0.31 ∆E ab over 7 hours . A safety evaluation of the technique is discussed which concludes that some caution should be employed when fading smooth, uniform areas of artworks. The instrument can also incorporate a linear variable filter. This enables the researcher to identify the active wavebands that cause certain degradation reactions and determine the degree of wavelength dependence of fading. Some preliminary results of fading experiments on Prussian blue samples from the paint box of J. M. W Turner (1755-1851) are presented.
The tensile properties of latex coatings were investigated with a set of custom formulated artist... more The tensile properties of latex coatings were investigated with a set of custom formulated artist-type paints at an age of 1 year. All films in the study contained a poly(methyl methacrylate-cobutyl acrylate) binder exhibiting a glass-transition at approximately 10°C. The viscoelastic behaviour of the latex matrix is first highlighted through a series of experiments involving different strain histories and temperatures.
The tensile properties of latex paint films containing TiO 2 pigment were studied with respect to... more The tensile properties of latex paint films containing TiO 2 pigment were studied with respect to temperature, strain-rate and moisture content. The purpose of performing these experiments was to assist museums in defining safe conditions for modern paintings held in collections. The glass transition temperature of latex paint binders is in close proximity to ambient temperature, resulting in high strain-rate dependence in typical exposure environments. Time dependence of modulus and failure strain is discussed in the context of time-temperature superposition, which was used to extend the experimental time scale. Nonlinear viscoelastic material models are also presented, which incorporate a Prony series with the Ogden or Neo-Hookean hyperelastic function for different TiO 2 concentrations.
Experimental Analysis of Nano and Engineering Materials and Structures, 2007
This is an introductory paper of a recent EC project dealing with research in cultural heritage a... more This is an introductory paper of a recent EC project dealing with research in cultural heritage and aiming to communicate new fields of application for optical metrology techniques. The project is in its initial state and more conclusive information is expected to be available at the time of the perspective conference. Nowadays safety, ethical, economical and security issues as well
The use of preventive conservation measures to assist in retarding the deterioration of painting ... more The use of preventive conservation measures to assist in retarding the deterioration of painting canvases has been suggested by the Conservation Department of the Tate Gallery [S. Hackney and T. Ernst, The applicability of alkaline reserves to painting canvases, in ...
Stephen Hackney (2016) Colour measurement of acid-detector strips for the quantification of volat... more Stephen Hackney (2016) Colour measurement of acid-detector strips for the quantification of volatile organic acids in storage conditions, Studies in Conservation, 61:sup1, 55-69, Acid-detector (A-D) strips were originally developed to assess the deterioration of acetate film stock, but they can also be used more generally within enclosures to detect volatile acidic pollution. A hand-held reflectance spectrophotometer was used to record the colour of individual strips in order to make consistent and reproducible readings. Calibration was carried out using the yellow-blue axis b*(D65) value in the CIELAB1976 system to measure the colour of A-D strips suspended in enclosed containers over solutions of acetic acid in combinations with glycerol to control the relative humidity (RH). A-D strips were found to be sensitive to changes in high RH (60-90%) but affected little by changes in lower RH or temperatures in the museum display and storage range. A-D strips can be used to establish the presence of volatile acids, record the indication of acid vapour concentration, explore conditions within a container, and to find sources of volatile acidity. They respond very quickly and several can be placed around an object. They therefore show promise for measuring slowly changing conditions, such as seasonal changes and the gradual accumulation of acidity in poorly ventilated containers and spaces. A-D strips proved useful in assessing air quality in storage and display enclosures. Examples and test results are presented. Wellsealed plywood transit frames and storage cases were found to be most polluted with volatile acids. Storage rooms with air filtration systems but filled with wooden objects had significantly reduced air quality.
Abstract: Examines the removal of dirt from some of Turner's unvarnished oil paintings: the ... more Abstract: Examines the removal of dirt from some of Turner's unvarnished oil paintings: the nature of the dirt on his unfinished paintings-greasy particles, smoke, sulphur dioxide; the adhesion of dirt-birding, absorption, etc.; cleaning-application on cotton wool swabs of ...
Speckle interferometry techniques with their high resolution full-field measurement capability of... more Speckle interferometry techniques with their high resolution full-field measurement capability offer a means of investigating the complex stress-strain behaviour of art objects under relatively low loading conditions. The focus of this paper is the investigation of art samples using the optical techniques of shearography and digital holography. A typical icon construction is a number of layers of egg tempera paint, gold paint and grounding on a wooden base. Oil paintings on canvas are typically composed of a number of layers of priming and oil paint on a canvas, with the canvas tension controlled by the stretcher. In both cases there is an opportunity for a complex stress field to develop as the canvas or wood expands or contracts at different rates to the paint and priming layers under changes in humidity and temperature. Shearography is a full-field optical technique, employing a common path shearing interferometer, which is sensitive to the displacement gradient. Digital holograp...
Shearography is a full-field optical technique usually used for non-destructive testing and for t... more Shearography is a full-field optical technique usually used for non-destructive testing and for the measurement of surface strains. This work is the development of a novel Impact Assessment Procedure (IAP), using shearography to collect the data about the condition of the artwork. This is a multi-step process with the first step being the recording of reference phase maps and the determination of signature features (anomalies in the phase map profile). After the artwork has undergone an impact which could possibly change its condition (e.g. transportation, malicious damage, conservation, aging) it is re-measured and the data is compared with the reference. The information obtained can be used by conservators to guide future conservation strategies on the artwork. This manuscript describes the development of a custom shearography prototype sensor for this purpose and the development of the IAP with a measurement programme on canvas and wooden panel painting samples.
Controlling Light with Light: Photorefractive Effects, Photosensitivity, Fiber Gratings, Photonic Materials and More, 2007
... 1Cédric Thizy, 1Marc P. Georges, 2Eleni Kouloumpi, 3Tim Green, 3Stephen Hackney,4Vivi Tornari... more ... 1Cédric Thizy, 1Marc P. Georges, 2Eleni Kouloumpi, 3Tim Green, 3Stephen Hackney,4Vivi Tornari 1 Centre Spatial de Liège Université de Liège, Liège Science Park, B-4031 Angleur, Belgium ... Two types of artwork are considered : wooden icons and textile canvas paintings. ...
O3A: Optics for Arts, Architecture, and Archaeology, 2007
This paper is one of a series submitted by the Multi-Encode Project consortium and covers the dev... more This paper is one of a series submitted by the Multi-Encode Project consortium and covers the development of holographic interferometry with dynamic photorefractive crystals. The aim of the first phase of the project is to assess the existing techniques for detection of signatures in various types of artworks. The trademark of our technique is a very high resolution in the fringe pattern. We will show the potentiality of our technique for the present application.
O3A: Optics for Arts, Architecture, and Archaeology, 2007
This is one of a series of papers submitted by the Multi-Encode Project consortium (006427 (SSPI)... more This is one of a series of papers submitted by the Multi-Encode Project consortium (006427 (SSPI)). Shearography, a full-field speckle interferometry technique, is applied to the investigation of movable cultural heritage. For this project a portable shearography sensor was ...
O3A: Optics for Arts, Architecture, and Archaeology, 2007
The design and experimental method for the use of a novel instrument for lightfastness measuremen... more The design and experimental method for the use of a novel instrument for lightfastness measurements on artwork is presented. The new microfadometer design offers increased durability and portability over the previous, published design, broadening the scope of locations at which data can be acquired. This reduces the need for art handling or transportation in order to gain evidence-based risk assessments for the display of light-sensitive artworks. The instrument focuses a stabilized high powered xenon lamp to a spot 0.25 millimeters (FWHM) while simultaneously monitoring color change. This makes it possible to identify pigments and determine the lightfastness of materials effectively and non-destructively. With 2.59mW or 0.82 lumens (1.7 x10 7 lux for a 0.25mm focused spot) the instrument is capable of fading Blue Wool 1 to a measured 11 ∆E ab value (using CIE standard illuminant D65) in 15 minutes. The temperature increase created by focused radiation was measured to be 3 to 4°C above room temperature. The system was stable within 0.12 ∆E ab over 1 hour and 0.31 ∆E ab over 7 hours . A safety evaluation of the technique is discussed which concludes that some caution should be employed when fading smooth, uniform areas of artworks. The instrument can also incorporate a linear variable filter. This enables the researcher to identify the active wavebands that cause certain degradation reactions and determine the degree of wavelength dependence of fading. Some preliminary results of fading experiments on Prussian blue samples from the paint box of J. M. W Turner (1755-1851) are presented.
The tensile properties of latex coatings were investigated with a set of custom formulated artist... more The tensile properties of latex coatings were investigated with a set of custom formulated artist-type paints at an age of 1 year. All films in the study contained a poly(methyl methacrylate-cobutyl acrylate) binder exhibiting a glass-transition at approximately 10°C. The viscoelastic behaviour of the latex matrix is first highlighted through a series of experiments involving different strain histories and temperatures.
The tensile properties of latex paint films containing TiO 2 pigment were studied with respect to... more The tensile properties of latex paint films containing TiO 2 pigment were studied with respect to temperature, strain-rate and moisture content. The purpose of performing these experiments was to assist museums in defining safe conditions for modern paintings held in collections. The glass transition temperature of latex paint binders is in close proximity to ambient temperature, resulting in high strain-rate dependence in typical exposure environments. Time dependence of modulus and failure strain is discussed in the context of time-temperature superposition, which was used to extend the experimental time scale. Nonlinear viscoelastic material models are also presented, which incorporate a Prony series with the Ogden or Neo-Hookean hyperelastic function for different TiO 2 concentrations.
Experimental Analysis of Nano and Engineering Materials and Structures, 2007
This is an introductory paper of a recent EC project dealing with research in cultural heritage a... more This is an introductory paper of a recent EC project dealing with research in cultural heritage and aiming to communicate new fields of application for optical metrology techniques. The project is in its initial state and more conclusive information is expected to be available at the time of the perspective conference. Nowadays safety, ethical, economical and security issues as well
The use of preventive conservation measures to assist in retarding the deterioration of painting ... more The use of preventive conservation measures to assist in retarding the deterioration of painting canvases has been suggested by the Conservation Department of the Tate Gallery [S. Hackney and T. Ernst, The applicability of alkaline reserves to painting canvases, in ...
Uploads
Papers by Stephen Hackney