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Colour Heritage and Conservation
Università Degli Studi Di Milano, Italy
19 - 24 October 2009
Below are the abstracts for the conference. More will be added as they become available.
Abstract: Artworks and Polychromy
University of Florence
The main purpose of this talk is to stress the importance of Polychromy in an artwork; from antiquity until present times, polychromy is quite often lost, and therefore frequently overlooked in studying and evaluating artefacts. This is an issue that needs a fresh reexamination, as without giving due consideration to this aspect of an artwork, one would not otherwise have the indispensable tools available for a proper comprehension of artistic phenomena.
Giorgio Bonsanti graduated in History of Art at the University of Florence in 1970; from 1968 to 1974 he worked as assistant of Charles de Tolnay, the Director of Casa Buonarroti in Florence; from 1982 to 1983 he was Scholarship Holder at Harvard University Centre of Villa Tatti I in Florence. From 1974 to 1979 he was the Director of the Galleria Estense and Superintendent in Modena; he was also the Director of Cappelle Medicee (1979-1982), San Marco Museum, Galleria dell'Accademia and Ufficio Restauri in Florence from 1979 to 1988; from 1988 to 2000 he was the Superintendent at the Opificio delle Pietre Dure, the national Conservation Institute based in Florence. From 1992 to 2000 he was a member of the Scientific Council for the Conservation of the Wall Paintings at the Courtauld Institute (London University); from 1995 to 1998 he taught at the Faculty of Conservation of the Cultural Assets of the University of Siena (branch of Arezzo) and, from 1995 to 1999, at the School of Specialization in Architectonic Restoration of Genoa. In March 2000 Giorgio Bonsanti became the first Italian Full Professor of "Conservation History and Techniques" (Turin University, Faculty of Sciences of the Formation). Currently he is Professor of "Conservation History and Techniques" at the University of Florence. From 1998 to 2000 he was the Responsible Director of the "O.P.D. Restauro" review and currently he's Scientific Expert for "Kermes", an Italian conservation review; since 1994 he has been writing for the "Giornale dell'Arte" review, where he is in charge of a monthly section called "Aperto per Restauri".
Bonsanti is the author of various publications about Giotto, Beato Angelico, Donatello, Michelangelo, Michael Pacher and Antonio Begarelli. He has presented papers at many Congresses and Conferences at several Cultural Institutes such as the National Gallery, the British Museum and the Courtauld Institute in London, the Harvard and Yale Universities, the Los Angeles J.P. Getty Museum, the Louvre of Paris, the Metropolitan Museum of New York and the Liebieghaus of Frankfurt. He has been a member of the Commission for the preservation of the Artistic Heritage of the Italian Republic Presidency, and is a member of the Commission for preventive conservation of the Louvre. He belonged for eight years to the Board of Trustees of the Teatro Comunale and Maggio Comunale Fiorentino, and for ten years (1985-1990, 1999-2004) he has been a member of the City Council in Florence. From October 2004 to March 2006 he was President of Firenze Mostre SpA. Since May 2003 he has been the Scientific Coordinator of CERR (Centro Europeo di Ricerche sul Restauro), an Institution of the City of Siena, and has been President of the Festival dei Popoli (international Festival of documentary films) in Florence since July 2004.
Abstract : S-Vis-NIR Spectroscopic characterization of glass * ICVBC-CNR, ** IFAC-CNR
Susanna Bracci* & Marcello Picollo**
Senior Chemist at ICVBC-CNR*, Researcher at IFAC-CNR**
Transparent or partially transparent objects, such as glass and stained windows, are usually studied in transmittance mode. This type of measurement can be performed either on small objects, by placing the analyzed sample in the sample compartment of a spectrophotometer, or on larger objects and on site guiding the radiation to the investigated object by using fiber optics accessories. In this case the measurement is usually accomplished by means of two collinear optical fibers at the opposite site of the investigated sample.
The visible portion of the acquired spectra can be used to calculate the colour coordinates of the analyzed object, while the UV-Vis-NIR spectra make it possible to identify the main chromophores.
The workshop includes a practical session that offers the participants a hands-on experience on the acquisition of spectroscopic measurements on glass samples.
Susanna Bracci graduated in chemistry from the University of Florence in 1988. From 1988 until 1996 she worked at the Instituto di Ricerca sulle Onde Elettromagnetiche “Nello Carrara” - National Research Council (CNR). Since 1996 she has been a researcher at the Centro di Studio sulle Cause di Deperimento e Metodi di Conservazione delle Opere d’Arte – National Research Council (CNR), which merged in 2002 with two other research centres to become the Istituto per la Conservazione e la Valorizzazione dei Beni Culturali – National Research Council (CNR). She collaborates with international chemical industries, Universities, Research Centers with projects focusing on the development of new products and new application techniques.
In the EU-ARTECH European project (2004-2009), she is the coordinator of the Joint Research Activity 1 – JRA1 “Development and evaluation of new treatments for the conservation-restoration of outdoor stone and bronze monuments”. She is responsible for the thematic research on “Ancient glasses” and is also a participant in several Italian teams acting as diagnostic support for conservation projects on works of art including sculptures, mosaics, painting.
Susanna is a member of the following: UNI-NORMAL [Joint-venture between Ente Nazionale Italiano di Unificazione and the Ministry for Cultural and Environmental Heritage (M.B.C.A.)] commissions: Working group GL3 “Chemical Metodologies”; Working group GL5 “Methods for the conservative treatments”; Working group GL7 “Physical methodologies”;
She is one of the Italian representatives in the European Committee for Standardisation CEN-TC346 (Conservation of Cultural Propert) in the Working Group 3 “Conservation Works”.
Marcello Picollo graduated in geology from the University of Florence in 1988. He is a researcher at the Institute of Applied Physics “Nello Carrara” (previously known as Institute for Research on Electromagnetic Waves, IROE) of the National Research Council of Italy (IFAC-CNR), Florence. He has been working on spectroscopic investigations of works of art since 1991. His main focus is on pigment characterization using non-invasive spectroscopic, imaging and X-ray techniques. In January 2009 he became the coordinator of the IFAC Applied Spectroscopy Group on the research line Integrated spectroscopic techniques for the non-invasive diagnosis, conservation and access to the objects of art (Tecniche spettroscopiche integrate per la diagnostica non invasiva, la conservazione e la fruizione del patrimonio culturale). At IFAC, he is the coordinator for two Scientific Collaborations: one between the University of the Balearic Islands, ICVBC-CNR, and IFAC-CNR, and the other between the National Institute of Information and Communications Technology (NICT), Tokyo, and IFAC-CNR. He is also the Asia and Oceania regional area chairperson for Infrared and Raman Users’ Group (IRUG) as well as the Coordinator of the Area Tematica del Colore Group of the Italian Archaeometric Association (AIAr).
Marcello Picollo provides analytical support to conservators and curators at museums, galleries, and restoration laboratories; oversees and performs testing and analysis on polychrome surfaces by using non-invasive techniques; supervises lab staff (Ph.D. students, junior fellows, interns, and technicians); monitors environmental conditions of art displays in galleries and churches; develops proposals for international research collaborations; functions as coordinator of international research projects.
Since October 2008, he has lectured at the Faculty of Sciences, University of Florence (Italy) on Image Elaboration for an undergraduate course in “Technology for the Conservation and Restoration of Cultural Heritage” and since January 2005, has lectured at the Faculty of Sciences, University of Ferrara (Italy) on Spectroscopic Techniques a graduate course in “Conservation and Diagnostic of contemporary and modern artworks”.
Abstract : Automatic techniques for digital colour restoration of movies:
Université de Reims Champagne-Ardenne (URCA), France
The cinematographic archives represent an important part of our collective memory. Since the 1950s, monopack colour film became the standard on which millions of cinematographic works were recorded. A couple of decades later, it turned out that this process was chemically unstable, causing the fading of whole film stocks with time. Since the bleaching phenomenon is irreversible, photochemical restoration of faded prints is not possible, hence the incontestability of digital colour restoration. Usually, a bleached colour release print is the only available record of a film and no reference colour is available, thus colour and dynamic range digital restoration is dependent on historical researches and on the skill of trained technicians who are able to control the restoration parameters. This can lead to a long and frustrating restoration process. For this reason, a restoration tool is a balance between a large number of complex restoration functions, to obtain accuracy in the result, and a limit on the number of these functions to maintain simplicity in the use.
In this workshop we will present some techniques and some leads to guide easily the restoration process using perceptual algorithms (ACE : Automatic Colour Equalization).
Majed Chambah is a CREATE partner and was the lead Organiser for Event 2 - “Putting the Human Back into Colour”. Majed received his Computer Vision and Image Processing MSc degree in 1998 from Université de Nice Sophia Antipolis in France. He obtained his Ph.D. in computer science and imaging in 2001 from Université de La Rochelle in France. He is currently working as a colour imaging scientist at CReSTIC (Centre de Recherche en Science and Technology of Information and Communication) in Reims, France. His current research interests are digital movie restoration, colour constancy, image enhancement, perceptual imaging and image quality.
Abstract : Cinema: moving towards all digital
CXLIM-SIC lab, Futurscope cedex, France
Since the DCI recommendations in 2005, the cinema industry is moving very quickly towards digital, and several thousands of digital systems have been installed during the last year; mainly in America and Europe. This can be seen as a real revolution in terms of capturing, post-producing, distributing and projecting cinema content. This presentation will report on what is happening and what is the digital effect from perceptual and cultural heritage points of view.
Dr. Chaker Larabi received his PhD from the University of Poitiers in 2002. He is currently associate Professor, in charge of the perception, colour and quality team. He is the president of French National Colour Imaging Group (GFINC) founded in 2002. His actual scientific interests deal with image and video coding and optimization, and more specifically image and video quality assessment. He works on the Human Visual System modelling (spatial, temporal and spatio-temporal) for the enhancement of several tools such as compression, digital cinema, etc. He is also a member of the French National Body for the ISO JPEG, since 2000 and chair of the Advanced Image Coding group. He is an active member of divisions 1 and 8 of CIE and a senior member of IEEE.
Abstract : Fibre Optics Reflectance Spectrometry and Pigment’s layer identification
Dipartimento di Fisica Università degli studi di Milano
Fiber Optics Reflectance Spectrometry (FORS) is an optical analysis wherein we measure the rate of diffuse light from a surface in dependence of the wavelength of the incident light (Spectral reflection factors). It can be used in pigment identification since the diffused light from different pigment layer are mostly characteristic.
The operating range in the e.m. spectrum can be from the UV region to the IR, in dependence on the detector and the light source used. Main detectors are made by Silicon, InGaAs or MCT, and optical fibres are used to drive and collect the light beam on the measure spot. The feature of this technique is the completely non-invasive method.
The purpose of this technique is the measure of the component of diffuse light in order to characterize the material of which the pigment is composed, studying the behaviour of the diffused spectra.
The application in the field of Cultural Heritage can be very important as a tool to obtain useful information about the pigments used and the artist’s technique, previous restoration intervention and an indirect dating of the materials. To perform the recognition, it is fundamental to have an extended database containing the most widespread sample of pigment layer including also mixtures and different binding.
Marco Gargano is technical researcher at the Department of Physics of the Università degli Studi di Milano, where, since 2004, he has dealt with diagnostics applied in Cultural Heritage. His research focuses on applied optical techniques: reflectance spectroscopy in UV-Vis-NIR for the characterization and identification of painting materials, Imaging technique: IR Reflectography, UV and visible photography applied on painting to reveal underdrawings and restorations, to verify and monitor the conservation conditions of paintings, and Thermography, which is an important method of non-destructive testing in historical building that allows researchers to detect degradation and hidden structure and to characterize building material. He also collaborates outside the Cultural Heritage field, where nevertheless use of these techniques provides interesting results in various cases: for instance, thermography for the assessment of stress in animals (rabbits) and the study of leaf antitraspirants, spectrophotometry and colorimetry in conservative dentistry.
Abstract: Pictorial restoration: techniques of integration of paint losses and their evolution to the present day
Syracuse University in Florence
This presentation will concentrate on the various methods and materials used by painting conservators to reconstruct areas of lost original colour on polychrome surfaces. The questions will be examined briefly from a theoretical and in more detail from a practical point of view, touching on the evolution of the various techniques, especially in Italy and Florence, from the 19th century to the present day. Emphasis will be placed on the various materials available and the methods of application most commonly put to use, and will also include a brief survey of recent methods developed to simulate the results of intervention, both by hand and computer aided.
With a Master of Arts from Syracuse University (New York) Florence Program in Renaissance Art History (1970), Diane Kunzelman has worked as an easel painting conservator at the Laboratorio di Restauro of the Opificio delle Pietre Dure in Florence, Italy, since 1977. She specialises in treatment of panel and canvas paintings dating from the medieval period to modern art. Her focus is on major conservation projects on works from the principle museums and churches in and around Florence, resulting in numerous publications, lectures, and contributions at international conferences. Her research is on painting materials and techniques and innovative methods of conservation of art works through non-invasive analysis, as well as computer simulation of restoration interventions.
Abstract: Colours for painting diagnostic: problems and experiences
Università degli Studi di Milano
Nicola Ludwig received his degree in Physics from University of Milan in 1991, and PhD in Science for the conservation of Cultural heritage at the University of Florence in 2004, with a thesis on Image spectroscopy.
He has been a researcher since October 2006 at the State University of Milano.
Initially working in the fields of atmospheric pollution since 1994, his main interests progressively shifted towards the use of infrared imaging in the field of non destructive testing on cultural heritage. He has worked as assistant at the cathedra of analytical method for the studies and conservation of cultural artworks (prof. M. Milazzo) and has developed both new instrumentation for infrared reflectography on paintings and new method for moisture detection by IR thermography. Collaborations include projects with Politecnico di Milano, Istituto Nazionale di Ottica Applicata - Firenze, Centre de Recherche et de Restauration des Musées de France (C2RMF) Louvre - Paris, and ICVBC - CNR Milano. His main research activities are: infrared thermography both applied for diagnosis of ancient buildings and for evapotranspiration rate in plant; infrared reflectography, visible-near infrared spectroscopy applied in pigment identification and colorimetric characterisation of renaissance painting techniques. In the field of colour imaging he has studied the problem due to the passage from films to digital images in well-established infrared and UV fluorescent techniques for painting diagnostic. In the last 15 years he has published more than 80 papers, mostly in the field of application of thermal imaging.
Abstract: Color Reproduction / Color Gamut Mapping:Two Sides of the Same Coin
Engineers like to compartmentalize complex problems into small sub-topics, so that each part can be analyzed and optimized. The assumption is that the whole is just the combination of all the subdivided parts. This approach works well when assembling a skyscraper. The metal parts have the same size and shape when assembled in the top, or the bottom of the building. Human vision is much more interesting. A part, such as an image pixel, can be any color appearance -- depending on the other pixels in the image structure. Artists have known for centuries that color appearances change with color surrounds.
Color engineers like to measure and transform color images one pixel at a time. Color engineers thing of color reproduction and color gamut mapping as two distinct topics, often discussed in separate books. In fact, they are the same problem.
All human color appearances can be described in a three-dimensional color space, with amounts of red, green and blue light as axes. Replicas are copies of an original using the same medium, or color materials, having the same physical properties for controlling light. Replicas share the exact same color space. Using the same materials means the color reproduction can be exact, as long as the illuminants are uniform.
Reproductions are copies of original art in a different medium, such as a computer-screen copy of a painting. The challenge in color reproduction is to copy the information contained in the entire original 3-D color space into a different size and shape reproduction space. The problem is very similar to moving. The original is one’s current house. (It is defined by the all the tools of physics used to measure light, such as wavelength, amount of light, etc.). The “reproduction” house has different dimensions for the length (amount of red), width (amount of green) and height (amount of blue). Reproductions move everything in the old house into the new house, keeping all contents in corresponding rooms, even though the dimensions of the entire house, and each room, are different. Good reproductions are never exact physical copies of the original, because that is impossible. Good reproductions capture the appearance and relationships of objects in the scene. The original and the reproduction have different 3-D color spaces with different sizes and local shapes, because they use different colorants. Good reproductions reproduce all the information in the interior of the original’s color space using completely different colorimetric colors at corresponding pixels.
Real scenes have the greatest range of light. Light emitting displays (TVs) have much less range, yet more than reflective prints. Dynamic ranges characterize the light reproduction values between the most and least response for each RGB channel, for each media. Color saturation characterizes the entire range of chroma of the medium’s colorants. Together range and chroma determine the color gamut, that is, all possible light values, of the medium. With greater color saturation of the dyes and filters, we find larger color gamuts. However, these pure colors are just 3, or 4, points in the entire color space. While the dyes and filters control the extreme boundaries, the quality of the reproduction depends on how the media presents the scene information in the interior of the color space. The term “tone scale” is used to describe how the media processing alters the interior of the original’s color space in the reproduction.
Some reproductions involve small transformations of the interior of the original’s, color space, such as a photographic print of an oil painting in uniform illumination. Real-life scenes, both indoor and outdoor, are almost always in non-uniform illumination. Illumination introduces a major challenge to reproduction by having an extremely large original color space. On a clear day shadows cast by the sun are 30 times darker than direct sunlight. Real-life scene reproduction is analogous to moving a castle into a cottage.
Imaging techniques can record scene information over a High Dynamic Range (HDR) of light. The range of captured information is much more than the 30:1 range possible between white and black in a reflective print. Ansel Adam’s Zone System provides the logical framework for capturing the wide range of light in natural scenes and rendering them in a smaller dynamic-range print. Adams described a three step process: measuring scene range, adjusting image capture to record the entire scene range, and locally manipulating the print exposure to render the high-range scene into the low-range print. Adams visualized the final image before exposing the negative. He assigned appearances from white to black to image segments. Once the negative recorded all the information, he controlled the local print contrast for each local part of the image (manually dodging and burning) to render all the desired information from a high dynamic range scene into a low-dynamic range print. Not only can these techniques preserve detail in high- and low-exposures, they can be used to assign a desired tone value to any scene element. Adams described the local contrast control in detail for many of his most famous images. Adams developed chemical and exposure manipulations to spatial control appearances between white and black. Today, we use Photoshop in digital imaging.
Painters have used spatial techniques since the Renaissance to render HDR scenes, and photographers have done so for 160 years. Retinex and Ace algorithms used the initial stage of Adam’s wide-range-information capture for its first stage. Instead of using aesthetic rendering, it adopted the goal that image processing should mimic human visual processing. These spatial processes writes calculated visual sensations onto prints, rather than writing a record of light from the scene. To this aim, spatial processing substitutes the original light values at each pixel with ratios of scene information. This approach preserves the content in the original found in the interior of the color space.
Electronic imaging made it possible, and practical, to manipulate images spatially. Automatic spatial processing is not possible in silver halide photography because film responds locally. Silver grains count the photons. The same quanta catch produces the same film density. Hence, Adams had to manipulate his images by hand. Digital image processing, or its equivalent, had to be developed in order for each pixel to be able to influence each other pixel, as in human vision. Details in the shadows are necessary to render objects in shade to humans. The accuracy of their light reproduction is unimportant: the spatial detail of objects in shadows is essential. Spatial-comparison image processing has been shown to generate successful rendering of HDR scenes. Such processes make use of the improved differentiation of the scene information. By preserving the original scene’s edge information, observers can see details in the shadows that are lost in conventional imaging.
A good color reproduction / gamut map conveys the appearance of the original. The interesting feature of excellent copies is that they do not reproduce the original’s stimulus. They cannot, any more than the mover can exactly reproduce the original house in a different size reproduction house. The image reproduction industry has developed high-chroma colorants, ingenious tone-scale and spatial-image processing techniques, so that they can make excellent reproductions. The secret is that they do not reproduce the original’s stimulus. What they do is more like rescaling the furniture for each room so that it has the same spatial relationship with other objects in the new size of room. Good reproductions retain the original’s color spatial relationships in the interior of the color space. They do this because they are indifferent to reproducing the light coming from the original. By definition, this is impossible for a reproduction/gamut map. It is only possible in a replica in uniform illumination.
John J McCann is a consultant on colour, colour imaging and image processing. He graduated from Harvard in 1964 with a degree in Biology. He had been working part- time for Polaroid as an undergraduate. In 1964 under the direction of Edwin Land he became the manager of the Vision Research Laboratory where his work on human psychophysics has included research on rods as colour receptors, low-spatial-frequency vision, mathematical models of colour vision and quantitative tests of Retinex theory. As Senior Manager in the Research Division of Polaroid, he directed the Vision Research Laboratory until retiring from Polaroid in 1996. From 1979 to 1996 he managed research on very-large format Polaroid photography, which includes the 20x24 cameras, the Museum Camera and Polaroid Replicas. In 1984 he was elected a Fellow of the SPSE (IS&T). In 1996 he as received SID’s Certificate of Commendation. He has served as Vice President, President and Past- President of the Society of Imaging Science and Technology. In 2003, he received the IS&T / OSA Edwin Land Medal and is OSA Fellow and IS&T Honorary member.
Abstract : The longevity of ink on paper for fine art prints
Senior Research Fellow CFPR, University of the West of England
With the emergence of digital imaging technologies in the 1980s, there followed a desire to print high quality colour images for artists. When Graham Nash and Mac Holbert, of Nash Editions USA, began printing using a Scitex Iris (3047) printer they realised that whilst the Iris technology produced beautiful, rich and dense colour, the dye-based inks were incredibly fugitive. They found that the early inks, if left in daylight for a few hours would fade.
This has been an ongoing problem for inkjet technology, and echoed by Henry Wilhelm’s paper How long will it last? An overview of the light-fading stability of inkjet prints and traditional color photographs (Wilhelm, 2002).
Since the 1980s, the quality of inks and papers has vastly improved, as has the print technology. By 2000, the three main wideformat manufacturers in the UK were shipping printers with inksets that contained pigment inks, so the early problem of a trade-off between brightness and longevity had been largely overcome. Printer manufacturers, working within Wilhelm testing parameters, also guaranteed print longevity of more than 100 years. This was good news if the print had been mounted and framed to archival standards. However, as wideformat printers were becoming larger and computers were able to process large image files, there was more opportunity to make very big prints that moved beyond the boundaries of the frame such as free hanging works and installation works. Particular examples were the room-sized pieces in Wolfgang Tilman’s exhibition, ‘If one thing matters, everything matters’ (6th June - 14th September 2003), at the Tate Britain, which demonstrated that as a gallery-sized work, the prints might be intended only for the lifetime of the exhibition. It is very likely that these works could be subjected to a similar environmental impact as snapshot photographs attached to the refrigerator door, or pinned to walls in offices and homes and subjected to ambient air (Wilhelm, 2007).
Artists working at the Centre for Fine Print Research are engaged in a range of digital printing and paper construction. This includes large-scale printing, and might be combined with other materials, such as stitching, screen inks, other printmaking processes, laser cutting, embossing and the surface of the paper might be dampened. These artworks might be stored in portfolios, in drawers, dry-mounted and unframed.
The problem is how to undertake an appropriate lightfast test, and the type of information that is useful to the artist in a real world situation in which light, humidity and temperature changes significantly over the year. As time and research into paper and ink has progressed, the research has highlighted that many parameters require consideration, which might have been beyond the initial scope of accelerated lightfast testing. Since 2005, a lightfast test project has been underway that considers real time exposure to printed materials. Ink on different paper samples have been subjected to a range of framed, unframed and storage conditions. This presentation will include theses results.
Carinna Parraman is senior research fellow at the Centre for Fine Print Research, University of the West of England, Bristol. She heads the C-Lab and is lead coordinator of this FP6 European project CREATE. Her objective is to facilitate dialogue between the fields of the arts, science and industry. Her interests are based on her artist background and in mixing pigmented colour for traditional printmaking. Her research has developed through long term usage of digital imaging software and print hardware and specialities that include developing alternative colour methods for artists and designers, bespoke digital colour printing, archiving of prints, image enhancement methods, and an ongoing assessment of current inkjet hardware.
As well as papers to the science, conservation and arts community, she exhibits fine art prints. Exhibitions have included: Drawing from Turner at Tate Britain (2007); Full Spectrum, A Colour+Chemistry at Sherborne House (2006) and AniGma Digital Art Show at the State Museum, Novorsibirsk, Siberia (2007).
Abstract: The Montelparo Polyptych, a restoration between art and science
Trinity College Rome
The material used in a work of art carries the message of the image and it does so in two ways, which can be defined as structure and appearance (from Brandi’s Theory of Restoration).
Brandi’s message is certainly pertinent when considering Colour Heritage, and I will show how in a work of art, as in any element of cultural heritage, this “appearance” is strictly interconnected with the structure. Following this principle we will see how work undertaken to preserve the wooden panels of a huge XV century painting is essential to secure the conservation of the paint layer and, consequently, the message of the masterpiece. It will be like a “restoration behind the scenes”.
We will talk about wood, its proprieties, the evolution in the field of wooden objects conservation, the studies to identify an appropriate new structure for our polyptych, and a documentary on all phases of the work done will be shown.
Francesca Persegati is a master conservator in the Vatican Museums Conservation Laboratory, and Senior Lecturer on the “Art Conservation Course” at the Trinity College Rome Campus. She received a Bachelor Degree for “Restoration and Conservation of Artistic Objects” at The Rome Central Institute for Restoration (1985) and Diploma for “Restoration and Conservation of Marble and Gypsum Objects” (1986).
Since 1981, she has been involved in a wide range of conservation projects, frescoes, stucco decorations, and paintings on canvas, panels, and fabric, including:
Since 1990 she has worked as a Restorer in the Paintings Conservation Laboratory in the Vatican Museums (Vatican City State), and was promoted to Master Restorer in 2006. She is the author of articles and handbooks on conservation, and has worked directly on most of the conservation projects that are covered in her degree course. Selected Restorations in the Vatican are:
Abstract :Image Diagnostics of Contemporary Art: some instances and perspectives
University and INFN - Ferrara
The research of new ways of expression of contemporary artists, the employment of new materials, often in different and astonishing assemblies, pose newer and newer problems in the conservation and documentation practice. As a consequence, new issues are required also in diagnostics protocols.
In this frame, emerging digital techniques – like 3D-scanning and Image Spectroscopy, for instance – may find extensive and useful applications. A large space for dedicated, innovative analyses is still unexplored but even well-known techniques, like grazing light photography, may find a new placement.”
Ferruccio Petrucci works in two branches of Experimental Physics: constructions of detectors of charged particles for High Energy Physics, and development of imaging techniques for applications to cultural heritage.
In the first area of work he collaborates on experiments NA48 and NA62 at CERN, devoted to the measurement of rare decays of kaon mesons.
In the second research field, he works on multi-spectral imaging for the conservation of works of contemporary art; on IR Reflectography with extended spectral range; on K-edge differential X-radiography; on the application of direct digital radiography.
His teaching activities, as associate professor at Ferrara University, are devoted to courses and laboratory in image diagnostics of works of art. He promotes and coordinates the graduate course in Conservation and Diagnostics of Modern and Contemporary Works of Art, active at Ferrara University since 2004/2005.
Abstract : Digital Video, digital cinema, and colour appearance
Independent contractor in the physics, mathematics, & engineering of digital colour imaging systems
I shall present an overview of digital video, HDTV, and digital cinema technologies, from acquisition, through processing, to display. I will concentrate on how creative intent is established and maintained through the chain, describing the manipulations that are necessary to produce visually acceptable portrayal of original works in the common case that viewing conditions differ between acquisition and display. I will describe issues of adapting visual material from one media to another, in particular, discussing issues associated with contrast ratio and colour gamut. I will describe successes and failures of using signal processing techniques to overcome differences in display and viewing conditions. We'll explore the boundary between classical colour science and emerging areas of colour appearance modelling.
Charles Poynton is an independent contractor specialising in the physics, mathematics, and engineering of digital colour (color!) imaging systems, including digital still cameras, digital video, HDTV, digital cinema (D-cinema) and digital intermediate (DI) systems. He is involved in engineering wide colour gamut systems, including xvYCC. HeesÊdo technology forecasting, systems modelling, algorithm development, video signal processing architecture, colour characterisation and calibration, and image quality assessment.
While at Sun Microsystems in Mountain View, California, from 1988 to 1995, he initiated Sun's HDTV research project, and introduced colour management technology to Sun. While at Sun, he launched the effort that established square sampling ("square pixels") as the standard for HDTV, and he established the number 1080 now found in HDTV standards. Prior to joining Sun, Mr. Poynton designed and built the digital video equipment used by NASA to convert video from the Space Shuttle into NTSC for recording and distribution.
Mr. Poynton is a Fellow of the Society of Motion Picture and Television Engineers (SMPTE), in 1994 was awarded SMPTE's prestigious David Sarnoff Gold Medal. He has organised and presented many popular courses and seminars. His book, "A Technical Introduction to Digital Video," was published in 1996 by John Wiley & Sons, and reached fifth printing. In February 2003, Poynton's second book "Digital Video and HDTV Algorithms and Interfaces" was the 3,339-th most popular item at Amazon.com. At present, he is a part-time Ph.D. student at Simon Fraser University.
He lives in Toronto with his wife Barbara and their two daughters.
Abstract : Seeing red: the beauty and complexity of colour vision
Materials Scientist, Conservation Department, Victoria and Albert Museum
Vision is the most sophisticated and developed of all human senses. For the vast majority of us, it dominates in our ability to assimilate and understand the world around us. Perception of colour is an intricate part of the visual process and the study of colour has occupied many of the greatest minds, both in science and in the arts. This talk shall look at what we mean by colour, how (and why) we see colour, and how we use colour vision in making sense of our surroundings. It shall explore some misconceptions commonly perpetuated about the nature and properties of colour and seeks to demonstrate a few of the many subtleties of human vision. The underlying message throughout the lecture is aimed at highlighting the key differences between seeing colour and measuring colour. It will conclude by presenting research on perceiving small colour changes and the role of this research in setting lighting strategies within a museum.”
Boris is a chartered physicist, chartered scientist, and member of the Institute of Physics, and has been the Materials Scientist in the V&A's Conservation Department since 1989. In 1994, he became the European coordinator of the Infrared and Raman Users Group (IRUG), going on to become one of the incorporators of the Group and member of the Board of Directors (2002) and then President (from 2006). He is currently the Coordinator of the ICOM Preventive Conservation Working Group (since 2008) and is a member of the editorial board of the Journal of Cultural Heritage. His research objective is to investigate the interactions between objects and their micro-environments, thereby increasing the effectiveness and longevity of conservation treatments, display and storage. His main duties at the V&A are to manage the Materials and Environment sub-section of the Science Section; conduct research into causes, effects, and means of reducing deleterious interactions; evaluate and advise on the suitability of display, storage and transport environments (including new major gallery projects); assess materials and lighting, particularly for construction of showcases and storage; give strategic advice to staff, other museums, and other professionals on technical matters; identify surface coatings, consolidants and corrosion products on artifacts; and to lecture on V&A and external courses.
Abstract : Colour changes in painted surfaces
Keeper, Department of Conservation and Scientific Research, British Museum
The effect of light on artist’s pigments is a well-researched area and the consequent colour changes to painted surfaces have been documented and recorded extensively. Increasingly there is a realisation that other colour changes are occurring or have occurred within paint layers that derive not solely from the action of light (although light sometimes exacerbates these effects). This presentation will review some of the chemical and physical changes in paint layers that cause the perceived colours to alter, spanning examples from Egyptian papyri to Elizabethan drawings and from twentieth century watercolours to Mediæval wall paintings. The effect of such changes on the historical and art historical interpretation of these works will also be considered and the implications of these studies for the future display and care of objects mentioned.
David Saunders is Keeper of the Department of Conservation and Scientific Research at the British Museum. He has a BSc (1981) and DPhil (1984) in Chemistry, and is Fellow of the International Institute of Conservation (FIIC). His areas of research include the scientific examination of artefacts, principally using non-destructive imaging and spectroscopic methods, studies of the deterioration of materials, particularly pigments, and preventive conservation. Prior to joining the British Museum he worked for twenty years in the Scientific Department at the National Gallery in London. He is a council member of the International Institute for Conservation (IIC) and was its Director of Publications from 2003 to 2009, editor of its journal, Studies in Conservation, from 1990 to 2009 and co-editor of the proceedings of its 2006 and 2008 congresses. He serves as an examiner for several conservation courses, on the International Advisory Board of the Courtauld Institute of Art wall paintings conservation course, on the Advisory Group for the AHRC/EPSRC Science and Heritage programme and as a trustee of the Anna Plowden Trust.
Abstract: Colorimetric calculations, colour appearance and colour rendering
Uni. of Pannonia, Virt. Environments. and Imaging Technologies Lab
Colorimetry is based on the assumption of additivity and proportionality, i.e. that radiation of different wavelength and intensities produce an additive sensation, where the latter is proportional to the stimulus. Recent investigations have shown both individual differences (observer metamerism) and the effect of adaptation. Based on these findings the fundamental colour matching functions need to be updated, and taken into consideration in the development of colour appearance models. Examples will be shown how these questions influence highly metameric colour matches, e.g. those made with coloured LEDs.
Above new findings have their consequences also on colour rendering, where at least two different questions have to be considered: colour fidelity, how accurately colours are reproduced if light sources of different spectral compositions are used, and colour preference that might influence the comfort feeling of people in a lit environment.
Examples how above can influence colour reproduction and the display of artefacts of cultural heritage will be shown.
Dr. János Schanda is Professor Emeritus of the University of Veszprém, Hungary. He graduated in physics at the Loránd Eötvös University in Budapest. The Hungarian Academy of Sciences granted him the degree of “Doctor of Technical Sciences” for his thesis work on colour rendering.
He retired from the Institute as Head of the Department of Optics and Electronics and joined the University of Veszprém as professor of informatics. He headed there the Department of Image Processing and Neurocomputing. Since retirement he is Professor Emeritus and advisor for the “Colour and Multimedia Laboratory”.
During the nineteen eighties and nineteen nineties he worked for the International Commission on Illumination (CIE) as its General Secretary and later technical manager. He functioned also in a number of honorary positions of the CIE. At present he is the Secretary of the Commission, is past Vice President, chaired and chairs several Technical Committees, among others dealing with fundamentals of photometry, colorimetry and colour rendering. At present he is the President of the Hungarian National Committee of the CIE.
Dr. Schanda is member of the Optical Society of America, of The Society for Imaging Science and Technology and of several Hungarian Societies in the fields of light and lighting and optical measurement. He served also on the Board of the International Colour Association (AIC) as its vice-president. He is on the editorial / international advisory board of Color Res. & Appl., USA, Lighting Research & Technology, UK and Journal of Light & Visual Environment, Japan. He is author of over 500 technical papers and conference lectures.
Abstract: Analytical methods of investigating colour in an art historical context
This presentation will communicate the results of an interdisciplinary study intended to advance the analysis of wall-paintings in the naves of four churches in the village of Arbanassi, Bulgaria. The overall impression conveyed by the interiors is that of colourful, sometimes rather intense decoration. However, despite the dominance of colour in the spatial experience of the spectator, colour has not previously been the subject of any detailed investigation into these interiors.
The paper explores a methodology based on the understanding that the appearance of colour is derived from the interrelation between ambient light and the surface of an object. Colourimetric measurements and calculations are employed in describing the appearance of the colours used in the churches. Account is taken of incandescent illumination of the kind used in these churches. The study demonstrates that, despite the perceived gulf between art and science, analytical methods of investigation of colour are, in some cases, the most appropriate way in which to advance art historical analysis of an image.
Elza Tantcheva began her career in science, as a post-graduate researcher in food technology. She worked on the use of colour as a qualitative indicator in the processing and preservation of food. The use of colour in art and design was another area of interest and after graduating in applied arts and monumental ceramics Elza worked as a designer in the textile and clothing industry. After a brief period studying in Finland she moved to the UK and established her own textile studio. In her artistic practice she became interested in the colour and symbolism of the Eastern Church and in her work she interprets the light and uses the colours found in church interiors. At present she is in the final stages of her DPhil, researching light and colour in the seventeenth century post-Byzantine churches of Arbanassi, Bulgaria. For this she has used scientific methods to aid the art historical interpretation of the church interiors.
Abstract: The history of the colour reproduction of artwork
Ravenna City Art Museum / University of Siena
Since the first appearance of black and white photographic technologies, the possibilities for reproducing artwork have changed. The mechanical “precision” of the camera lens has taken the place of the engraver’s eyes. A new specific code, used to translate the original message in a monochromatic way, has been defined, thus avoiding problems linked to the appearance of the colours. In the twentieth century, thanks to important inventions that allow “true” colour reproduction, photographically reproduced artwork started to appear in colour.
Today, the colour reproduction of artwork has almost completely replaced black and white reproduction in books, in slides and on computer screens.
This presentation will focus on the history of the colour reproduction of artwork, through the analysis of significant aspects, such as the technologies employed, publishing, the development of the first colour archives, the position of art critics and the constantly changing appearance of the images. Particular attention will be given to an editorial product: a series of monographic issues dedicated to the most important ancient and modern painters; this type of publication, very widespread today, first appeared at the beginning of the twentieth century.
I graduated with a degree in Conservation of Cultural Heritage from the University of Bologna.
I received a Master’s degree in the History, Preservation, Restoration of the Pictures on Wall, Table and Canvas from Middle Ages to Contemporary from the University of Bologna.
I am currently PhD candidate in Art History at the University of Siena where I am carrying out research with a focus on the history of the colour reproduction of artwork.
I am employed, with fellowship, at the Ravenna City Art Museum; my responsibilities include archival and bibliographic research and cataloguing information on the history, conservation and restoration of ancient and modern mosaics (the database is available on the web site www.mosaicocidm.it).
I am an assistant professor at University of Bologna where I am responsible for the organisation of tutorials and seminars on the history of art restoration and conservation, the visual perception of colour and issues concerning art restoration and its relationship to visual culture.
In 2007, I published a book entitled La percezione del colore nella pratica del restauro, thanks to the publisher, Edifir.
Abstract: 2-dimensional digital imaging of artworks: general aspects and the issue of colour accuracy
Institute of Applied Physics of the National Research Council (IFAC-CNR)
Nowadays there are several possible workflows to get colour accuracy using different data structures (icc profiles, dcp profiles, standard colour spaces) and different software tools available on the market (conversion calibrators, dng profiler, tiff profiler). After an overview of operational practices for image digitization of artistic and cultural-historical artefacts, the presentation will focus on a specific aspect of digitization: the colour.
A review of traditional and innovatory different workflows will be presented and a comparative evaluation among their performances will be carried out, using both colorimetric indicators and considerations concerning operational aspects. Some future perspectives on colour accuracy will be discussed.
Giorgio Trumpy was born in 1980 and grew up in Livorno (I). He received his BSc degree in Technologies for Conservation and Restoration of Cultural Heritage from the University of Florence in 2004; the key topic of his thesis was the identification of the pigments present on 19th and 20th century paintings by means of UV-Vis-NIR reflectance spectroscopy. From 2006 he has been working on the project of digitization of the Florentine Museums heritage, collaborating with several public and private entities like the Institute of Applied Physics (IFAC-CNR), the Rinascimento Digitale Foundation, the Institute of Restoration Opificio delle Pietre Dure, Centrica s.r.l., the Chamber of Commerce of Florence. The digitization process of cultural objects, in particular the stage of image acquisition, is his main research topic; practical (assistant during photographic acquisition of artworks, post-processing and monitoring the quality of digital images) and teaching (editing of manuals, relator of courses and seminars) activities make a part of his regular job too. He participated at several conferences in the field of digital imaging, colour science, science for conservation of art and he published for international and national reviews. His actual main interest, that is also the topic of his MSc thesis, is the development of an adjustable system for the creation of ICC profiles in case of small colour gamut digital images.
Abstract: Colour and the restoration of motion picture film
Technical Projects Officer, British Film Institute National Archive
The cinema has been coloured throughout its history. Film restoration, one of the youngest disciplines of conservation, is characterised by the necessity of duplication – the original artefacts cannot be displayed as they were originally but must be reproduced using contemporary materials.
For these reasons, the techniques of film restoration have been closely linked to norms of film post-production. There is now a growing use of digital intermediate methods. How will this affect the restoration and exhibition of archive collections? What archival considerations are involved in reproducing a film for both film and digital projection and for DVD release?
This presentation will use recent restoration work by the BFI’s National Archive as case studies of the pragmatic nature of film archiving. Examples will include films from the 1930s made in the Dufaycolor system; the work of film artist Jeff Keen (b.1923) in the sixties and seventies; as well as some of the many colour systems prevalent in the silent era.
Kieron Webb is currently Technical Projects Officer at the British Film Institute’s National Archive. He has worked on the restorations of both Charlie Chaplin’s and David Lean’s first films. This year’s Cannes Film Festival premiered the restoration of Accident (1967), which he led. He is about to work on The Great White Silence (1924), the film record of Scott’s Antarctic expedition.
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