Linda Cocchi - Academia.edu (original) (raw)
Papers by Linda Cocchi
The Deformometric Kit (DK) is a measurement system able to give continuously and real time quanti... more The Deformometric Kit (DK) is a measurement system able to give continuously and real time quantitative information on the deformational dynamic response of panel paintings and other cultural wooden objects when they are subjected to environmental hygrothermal fluctuations. Using two parallel transducers linking a pair of axes fixed to the back of a panel, both the linear extension and the mean curvature of a studied zone can be monitored. To date many applications on actual panel paintings have been performed both in churches and in museums. We have monitored crosses, altarpieces, triptychs, placed in their usual display locations. As result of these experiences, new questions arise also of concern related to curators and restorers needs. The presentation will focus on the most challenging measurement needs under current investigation: - Monitoring strains/stresses during handling and transportation, requiring a particular use of the DK. Some data have been collected during various...
Since 2004, the “Mona Lisa” painting by Leonardo da Vinci has been studied by an international re... more Since 2004, the “Mona Lisa” painting by Leonardo da Vinci has been studied by an international research group of wood scientists and several experimental campaigns have been carried out to understand its characteristics and provide indications for its conservation. Based on the collected data, a numerical model of the wooden panel has been developed to simulate the mechanical interaction with the framing system. The main objective of this modelling work, described in this paper, is to extract as much information as possible from the experimental tests carried out and, thus, reach a sufficient level of scientific knowledge of the mechanical properties of the panel to build a predictive model. It will be used to predict the effect of modified boundary conditions and as a tool of preventive conservation.
A series of laboratory tests were conducted on a commercial device for active relative humidity c... more A series of laboratory tests were conducted on a commercial device for active relative humidity control of display cases to assess the ability of the machine to control a medium format (3.45 m3) museum display case. An extreme museum environment with large relative humidity and temperature fluctuations was simulated and different air leakage rates were produced (0.1 0.5 6 AER/day) on a purposely-made display case. The machine was shown to work very effectively for both in humidify and dehumidifying for conditions corresponding to very well sealed ( AER 0.1) to medium sealed (AER 0.5). On a very poorly sealed enclosure (AER 6), the external environmental fluctuation resulted in internal fluctuations but the machine very effectively mitigated these effects. The use of the machine in positive pressure mode and (optional) recirculating mode was shown to be irrelevant to the ability of the machine to control the relative humidity. Positive pressure mode provides a constant flow to remove...
HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific r... more HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L’archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d’enseignement et de recherche français ou étrangers, des laboratoires publics ou privés. Experimental studies on the wooden support of the ”Mona Lisa” Luca Uzielli, Joseph Gril, Linda Cocchi, Julien Colmars, Paolo Dionisi Vici, David Dureisseix, Giacomo Goli, Delphine Jullien, Bertrand Marcon, Paola Mazzanti, et al.
Since 2004 an international research goup rof Wood Technologists has been given by the Louvre Mus... more Since 2004 an international research goup rof Wood Technologists has been given by the Louvre Museum the task of analysing the mechanical situation of the wooden panel on which Leonardo da Vinci painted his “Mona Lisa”, possibly between 1503 and 1504. The general purpose of such study was to evaluate influences which could possibly derive from environmental fluctuations in the showcase where the painting is exhibited, and any measure which could improve its conservation conditions. In order to acquire data about the mechanical behaviour of the panel, and to feed and calibrate appropriate simulation models, the team has not only set up a continuous monitoring by means of automatic equipment, but has also performed manual measurements on the occasion of the annual openings of the showcase where the masterpiece is conserved and exhibited.
Data Revues 12962074 Unassign S1296207412000507, Jan 5, 2012
Studies in Conservation, 2016
This study deals with the post-treatment evaluation of the elastic crossbar system already design... more This study deals with the post-treatment evaluation of the elastic crossbar system already designed and installed on the recently restored panel painting Deposition from the Cross by an anonymous artist from Abruzzo (sixteenth century). After the restoration, the panel and the crossbars were subjected to mechanical tests to identify their elastic characteristics. Then the panel, equipped with the elastic crossbar system, was subjected for about two months to controlled environmental cycles made up of approximately constant humidity periods. During the two months, the forces exerted by the springs and the deformations of both panel and crossbars were continuously monitored. A mathematical model, calibrated on the specific parameters derived from the analysis of the panel, provided the deformation that the panel would have shown without the crossbars; comparing the model output with the measured data provided a restraining effect (RE) of approximately 7% (RE could range between zero – no restraint – and 100% – total restraint). Future developments of this project will define appropriate procedures to design an elastic crossbar system for a given panel, once the expert judgement of restorers has identified the most desirable RE to be achieved.
Journal of Cultural Heritage, 2012
This paper describes the "Deformometric Kit" (DK), which is both a methodological approach and an... more This paper describes the "Deformometric Kit" (DK), which is both a methodological approach and an equipment conceived, designed and made at DEISTAF (University of Florence). The DK's main purpose is to carry out measurements and monitoring of the deformation dynamics of wooden objects. The monitoring can take place in virtually any environment, for any desired duration (minutes, hours, weeks, years, and so on). The measurement can be carried out mainly, but not exclusively, in connection with fluctuations of ambient temperature and relative humidity. The DK provides a reliable and accurate record (a first step towards understanding) of the behaviour of original panel paintings placed in their usual exhibition location, enabling curatorial staff and researchers to (a) obtain information about the behaviour of individual supports, in order to evaluate the impact of climate on their conservation state, help to make decisions for future restoration interventions; and (b) provide reference data for calibrating and validating numeric models. It can also provide data on the deformation of a panel while it is handled and transported, enabling an evaluation of stresses to which it is subjected during this operation. The device consists of two displacement transducers, which are fixed (in a low-impact, reversible way) to the back face of the panel, perpendicular to the grain, at different distances from the panel's surface. The two transducers not only measure the in-plane shrinkage/swelling of the panel, but since they are located at different distances, their measurements can also be combined with simple geometrical calculations to indicate the amount of distortion (cupping) which the panel undergoes. This paper explains the geometrical principles on which the DK is based, as well as its construction. Some examples of the data which have been obtained during actual monitoring by the DK are also included. This paper describes a method used to monitor the deformation dynamics of panel paintings, based on the use of two transducers measuring the relative movement of two columns fixed on the back of the panel. It can be used in many contexts of conservation studies, like evaluating the effects of environmental variations or of handling and transportation, for supporting decisions about future restoration interventions, for providing reference data for calibrating and validating computer models.
Journal of Cultural Heritage, 2012
The Deformometric Kit (DK) is a measurement system able to give continuously and real time quanti... more The Deformometric Kit (DK) is a measurement system able to give continuously and real time quantitative information on the deformational dynamic response of panel paintings and other cultural wooden objects when they are subjected to environmental hygrothermal fluctuations. Using two parallel transducers linking a pair of axes fixed to the back of a panel, both the linear extension and the mean curvature of a studied zone can be monitored. To date many applications on actual panel paintings have been performed both in churches and in museums. We have monitored crosses, altarpieces, triptychs, placed in their usual display locations. As result of these experiences, new questions arise also of concern related to curators and restorers needs. The presentation will focus on the most challenging measurement needs under current investigation: - Monitoring strains/stresses during handling and transportation, requiring a particular use of the DK. Some data have been collected during various...
Since 2004, the “Mona Lisa” painting by Leonardo da Vinci has been studied by an international re... more Since 2004, the “Mona Lisa” painting by Leonardo da Vinci has been studied by an international research group of wood scientists and several experimental campaigns have been carried out to understand its characteristics and provide indications for its conservation. Based on the collected data, a numerical model of the wooden panel has been developed to simulate the mechanical interaction with the framing system. The main objective of this modelling work, described in this paper, is to extract as much information as possible from the experimental tests carried out and, thus, reach a sufficient level of scientific knowledge of the mechanical properties of the panel to build a predictive model. It will be used to predict the effect of modified boundary conditions and as a tool of preventive conservation.
A series of laboratory tests were conducted on a commercial device for active relative humidity c... more A series of laboratory tests were conducted on a commercial device for active relative humidity control of display cases to assess the ability of the machine to control a medium format (3.45 m3) museum display case. An extreme museum environment with large relative humidity and temperature fluctuations was simulated and different air leakage rates were produced (0.1 0.5 6 AER/day) on a purposely-made display case. The machine was shown to work very effectively for both in humidify and dehumidifying for conditions corresponding to very well sealed ( AER 0.1) to medium sealed (AER 0.5). On a very poorly sealed enclosure (AER 6), the external environmental fluctuation resulted in internal fluctuations but the machine very effectively mitigated these effects. The use of the machine in positive pressure mode and (optional) recirculating mode was shown to be irrelevant to the ability of the machine to control the relative humidity. Positive pressure mode provides a constant flow to remove...
HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific r... more HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L’archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d’enseignement et de recherche français ou étrangers, des laboratoires publics ou privés. Experimental studies on the wooden support of the ”Mona Lisa” Luca Uzielli, Joseph Gril, Linda Cocchi, Julien Colmars, Paolo Dionisi Vici, David Dureisseix, Giacomo Goli, Delphine Jullien, Bertrand Marcon, Paola Mazzanti, et al.
Since 2004 an international research goup rof Wood Technologists has been given by the Louvre Mus... more Since 2004 an international research goup rof Wood Technologists has been given by the Louvre Museum the task of analysing the mechanical situation of the wooden panel on which Leonardo da Vinci painted his “Mona Lisa”, possibly between 1503 and 1504. The general purpose of such study was to evaluate influences which could possibly derive from environmental fluctuations in the showcase where the painting is exhibited, and any measure which could improve its conservation conditions. In order to acquire data about the mechanical behaviour of the panel, and to feed and calibrate appropriate simulation models, the team has not only set up a continuous monitoring by means of automatic equipment, but has also performed manual measurements on the occasion of the annual openings of the showcase where the masterpiece is conserved and exhibited.
Data Revues 12962074 Unassign S1296207412000507, Jan 5, 2012
Studies in Conservation, 2016
This study deals with the post-treatment evaluation of the elastic crossbar system already design... more This study deals with the post-treatment evaluation of the elastic crossbar system already designed and installed on the recently restored panel painting Deposition from the Cross by an anonymous artist from Abruzzo (sixteenth century). After the restoration, the panel and the crossbars were subjected to mechanical tests to identify their elastic characteristics. Then the panel, equipped with the elastic crossbar system, was subjected for about two months to controlled environmental cycles made up of approximately constant humidity periods. During the two months, the forces exerted by the springs and the deformations of both panel and crossbars were continuously monitored. A mathematical model, calibrated on the specific parameters derived from the analysis of the panel, provided the deformation that the panel would have shown without the crossbars; comparing the model output with the measured data provided a restraining effect (RE) of approximately 7% (RE could range between zero – no restraint – and 100% – total restraint). Future developments of this project will define appropriate procedures to design an elastic crossbar system for a given panel, once the expert judgement of restorers has identified the most desirable RE to be achieved.
Journal of Cultural Heritage, 2012
This paper describes the "Deformometric Kit" (DK), which is both a methodological approach and an... more This paper describes the "Deformometric Kit" (DK), which is both a methodological approach and an equipment conceived, designed and made at DEISTAF (University of Florence). The DK's main purpose is to carry out measurements and monitoring of the deformation dynamics of wooden objects. The monitoring can take place in virtually any environment, for any desired duration (minutes, hours, weeks, years, and so on). The measurement can be carried out mainly, but not exclusively, in connection with fluctuations of ambient temperature and relative humidity. The DK provides a reliable and accurate record (a first step towards understanding) of the behaviour of original panel paintings placed in their usual exhibition location, enabling curatorial staff and researchers to (a) obtain information about the behaviour of individual supports, in order to evaluate the impact of climate on their conservation state, help to make decisions for future restoration interventions; and (b) provide reference data for calibrating and validating numeric models. It can also provide data on the deformation of a panel while it is handled and transported, enabling an evaluation of stresses to which it is subjected during this operation. The device consists of two displacement transducers, which are fixed (in a low-impact, reversible way) to the back face of the panel, perpendicular to the grain, at different distances from the panel's surface. The two transducers not only measure the in-plane shrinkage/swelling of the panel, but since they are located at different distances, their measurements can also be combined with simple geometrical calculations to indicate the amount of distortion (cupping) which the panel undergoes. This paper explains the geometrical principles on which the DK is based, as well as its construction. Some examples of the data which have been obtained during actual monitoring by the DK are also included. This paper describes a method used to monitor the deformation dynamics of panel paintings, based on the use of two transducers measuring the relative movement of two columns fixed on the back of the panel. It can be used in many contexts of conservation studies, like evaluating the effects of environmental variations or of handling and transportation, for supporting decisions about future restoration interventions, for providing reference data for calibrating and validating computer models.
Journal of Cultural Heritage, 2012