• Titolo: APLAR 5. Applicazioni laser nel restauro.
  • Atti del convegno. Musei Vaticani 18-20 settembre 2014.
  • Curato da: Anna Brunetto
  • Editore: Nardini Editore
  • Data di Pubblicazione: agosto 2017
  • ISBN: 978-88-404-0078-5
  • Pagine: 584
  • Formato: illustrato in b/n, copertina 4 colori, brossura, 21x28 cm
  • Costo di copertina 33,00 euro
INDICE
Presentazione, Antonio Paoluccip. 11
Introduzione, Anna Brunettop. 12
La tecnologia laser nella pulitura dei manufatti lapidei: casi studio a confronto
R. Licciardi, M. Mascalchi, S. Siano, B. Megna Continua...
Abstract
Aim of this paper is evaluating stone cleaning efficiency of different Nd:YAG laser (λ 1064 nm) regimes, i.e. Short Free Running and single, double or triple pulse Long Q-Switch. Three stone artefacts affected by different conservation problems characterized by means of microRaman, Vis-NIR Reflectance and colorimetry, underwent laser ablation tests using the different operating conditions available in order to individuate damage threshold and suitable fluence range. Cleaning results were evaluated analysing polished cross sections observed in optical microscopy, both visible and UV, and electronic microscopy coupled with EDS. In order to obtain a sharp and selective cleaning method, matching the different artefacts' characteristics, pros and cons of every ablation rate were weighed. Results of this work confirm the potential of laser cleaning, highlighting the need of having at one's disposal several laser temporal regimes to choose the most suitable for every case. Chiudi
p. 15
Rimozione laser di biodeteriogeni da manufatti lapidei: definizione dei parametri di irragiamento e valutazione analitica
M. Mascalchi, I. Osticioli, S. Siano Continua...
Abstract
The periodical removal or impairment of biodeteriogens represents a fundamental need in the preservation of outdoor stone cultural heritage. In the present work, we have investigated the potential of laser treatments of lichens and biofilms from Carrara marble artefacts. Irradiation tests have been carried out on seriously deteriorated marble slabs from the monumental tombs of the English Cemetery of Florence using different wavelengths (532, 1064 and 2940 nm) and pulse durations (10 ns, 40-120 µs and 400 µs). The effects of laser tests have been characterized using various analytical techniques (optical and electronical microscopy, colorimetry, etc.). In particular, Chlorophyll Fluorescence with Pulsed Amplitude Modulated (CF-PAM) has allowed quantifying the impairment effects to the outer phototrophic organism residues, while the damage to the endolithic growths has been evaluated by means of stratigraphic analysis using optical microscopy and SEM examinations following osmium tetroxide staining of cytoplasmic lipids. Chiudi
p. 31
Due casi di pulitura laser a 532 nm: sarcofago e materiali cartacei
J. Striber, M. Frankovic, M. Jovanovic, M. Jelenic Continua...
Abstract
In this workthree different wavelengths of Nd:YAG laser were used in Q-Switched regime, with the aim of removing the deposited layers on artwork objects' surfaces and the effects of laser irradiation on these objects were monitored. For this purpose, objects having different structure and different type of depositions were used: limestone sarcophagus from the Heritage Museum – Ruma and paper documents from the Archives of Yugoslavia. Sarcophagus from Late Antiquity was covered with a layer of lichens. The experiment was carried out in order to determine the optimal laser cleaning parameters, varying the wavelengths and energy. In the case of the sarcophagus, the best results were obtained when combining two wavelengths: 1064 nm and 532 nm. To verify the efficiency of removal of lichens from the limestone surface, digital microscope was used, with magnification of x 400. It hasshown that lichens were removed completely, without any damage to the surface of limestone. In this way, laser cleaning proved to be a suitable substitute to the use of mechanical or chemical methods that could potentially cause damage to the surface in the long run. The other case study was quite different, concerning paper, an organic material surface, that was covered with inorganic foxing stains, composed of iron oxides. However, as in the first case, by varying the laser parameters – wavelength and energy, the experiment yielded the optimal results, the green wavelength proving to be the most efficient and not harmful to the surface of the paper. To analyse the efficiency of cleaning, i.e. removal of the oxides, the XRF and colorimetric measurements were used. In order to analyse the effects that the process of laser cleaning has produced on paper itself, two instruments were used: digital microscope, and the “mouse” microscope with a magnification of x 20, with two IR and two UV laser diodes, and with two modes of radiation: front and grazing. Chiudi
p. 45
Effetti della radiazione laser su transenne in stucco gessoso e selenite da Santa Sabina in Roma
F. Aramini, P. Biocca, A. Brunetto, L. Conti, C. Giovannone, V. Massa, S. Pannuzi, G. Sidoti Continua...
Abstract
During the restoration activities laser cleaning tests were carried out on some transennas, made of plaster gypsum and selenite, coming from the window of the paleochristian church of Saint Sabina in Rome. The originary materials and their alteration forms were characterized by several investigation technology: digital and optical video microscopy, scanning electron microscopy equipped with energy dispersive X-ray analysis system (SEM-EDX), micro-Fourier Transform Infrared Spectroscopy (micro-FT-IR), Thermogravimetric analysis (TGA) and visible induced photoluminescence (VIL). Different type of lasers were used for cleaning tests: Nd:YAG, wavelength 1064 nm in pulse mode LQS (100 ns) and SFR (30-110 µs), Nd:YAG wavelength 1064 nm and 532 nm pulse mode QS (8 ns). The control and the effectiveness of laser removal were evaluated by surface analysis and measurement of macroscopic thermal effects induced on non-originary materials and on transennas. Chiudi
p. 57
L’intervento di restauro del gruppo di Ganimede con l’aquila, Galleria degli Uffizi, Firenze
S. Landi, D. Manna Continua...
Abstract
The essay presents the results of the restoration work on the sculpture Ganymede with the eagle, realized in the Ist century a.C. and purchased in 1584 by Cardinal Francesco de 'Medici, thus becoming part of the Medici collections. The sculpture is in white veined marble and shows substantial reconstructions and dowels, which are the results of several interventions over the centuries. Before the restoration the whole marble surface was particularly dark, blurred by coherent and incoherent deposits and by a thick yellowish patina, likely the alteration of ancient treatments. After a first careful dusting, a soft cleaning with cotton swabs soaked in demineralised water has been realized, followed by localized applications of compresses with solvents. Then, some laser tests were made using the Nd:YAG EOS 1000 tool, provided by the El.En. company. Being the tests effective, the laser technique was used on the different areas, selectively defining the best parameters for each portion and integration. Therefore, the laser ablation let preserve the original patina and offered to the sculpture a coherent aspect. Chiudi
p. 73
Applicazione del laser nella pulitura di opere lapidee: esperienze recenti ai Musei Vaticani
E. Bottacci, V. Felici, V. Lini, G. Mori, R. Sánchez Del Pozo, S. Spada Continua...
Abstract
In the last few years the application of laser technologies at the Marble and Casts Restoration Workshop of the Vatican Museums was increasingly adopted. Most of the times it was just one more cleaning technique among the other chemichal, biological and mechanical ones based on the same theoretical approach. In the variety of the given examples, the laser cleaning was sometimes resolutive; in some other cases, it showed a narrow applicability range or even not surmountable limits. The present report accounts on successful data related to laser cleaning of stone materials, grouped for specific treated issues such as: incrustations, root apparatuses, traces of colour or writings, coatings (also on plaster additions), not specifically defined layers or organic substances. According to the cases, the goal was to remove, reduce, discolour, or preserve the single situation. colour changes. The wavelenght used was the 1064 nm, Nd:YAG source, in a SFR, QS or LQS system, or in their sequential combination. A synopsis of collected data recorded by the single restaurators proved to be very helpful for sharing, investigating and comparing experiences, each of which never alike the others, and yet meaningful for finding similar applied parameters. Chiudi
p. 83
La pulitura di un’urna romana con il laser Er:YAG a 2940 nm
A. De Cruz, A. Andreotti Continua...
Abstract
A Roman Cinerary urn, 67-100 CE, was acquired by the St. Louis Art Museum in 1922 and never exhibited because of the intractable encrustation which covered the decorative area of the marble surface. It was sent to the conservation laboratory at Duke University for cleaning with the pulsed free running Er:YAG laser at 2.94 µm. A preliminary investigation of the material has been performed by means of chromatographic mass spectrometric technique (GC/MS), Scanning Electron Microscope-EDX analysis (SEM-EDX) and Micro-Raman Spectroscopy. The GC/MS analyses highlighted the presence of a proteinaceous material (egg), and of a source of another lipid material. The hard encrustation that obscured the carving of the Roman urn was removed using a laser power of 200 mW (in presence of alcohol: water 1:1 as wetting agent) leaving a compact thin layer of calcium oxalate on the marble surface. Chiudi
p. 101
Rimozione di scritte vandaliche da pietra di Vicenza con tecnologie laser e plasma atmosferico
M. Favaro, I. Sacco, L. Tresin, A. Brunetto, F. Faleschini, L. Nodari, A. Patelli, E. Verga Falzacappa, P. Scopece, S. Voltolina Continua...
Abstract
In the last decades the problem of vandalism damage by written spray paint, so called graffiti, on monumental surfaces has become increasingly relevant. The necessity of remove them is a very striking issue, linked both to the appropriate restoration and to the high costs of removal and maintenance. The purpose of this experimentation was to evaluate the efficiency in graffiti removal through the use of laser and atmospheric plasma. The two methodologies were tested on laboratory mockup sample and, once found the best working condition, on real Cultural Heritage object. The experimentation were monitored by using optical and electronic microscopy, colorimetry and FTIR spectroscopy. The results have shown that both the techniques can be exploited in graffiti removal, especially when they are coupled with a solvent treatment. At the same time we observed that he efficiency in removal is dependent from the substrate porosity. Chiudi
p. 111
Rimozione delle scritte a pennarello dalle superfici in marmo: approccio fisico-chimico
B. Salvadori, M. Del Colle, S. Caciagli, E. Cantisani, B. Agostini, V. Trafeli, R. Fontana, J. Striova Continua...
Abstract
In the present work we report on the systematic study of the removal of sings by felt tip pens from the marble substrates by means of physical (laser) and chemical means. The advantage of combined approach is based on the preliminary removal of the superficial colorant layers by pulsed laser radiation at 532 nm so as to minimize the risk of the further colorant diffusion into the internal stone structure caused by the potentially more efficient solvent-based cleaning that is performed in the second step. The outcome is demonstrated on the removal of three markers (red, blue and black) of two brands (Uniposca, Marker) from unaged marble substrate. The typology of markers was chosen in agreement with the most diffused types of vandal acts by felt tip pens on stone artworks in Florence (Florence cathedral). For the chemical approach two commercially available products indicated for the removal of graffiti were tested Tergent (Geal) e Art-Shield4 (CTS). The cleaning efficiency, for single cleaning step (laser Nd:YAG, chemical products) and when applied in sequence (laser+chemical cleaning), was evaluated by colorimetric measurements and optical microscopy. Chiudi
p. 121
Il Cristo Svelato: rimozione di ossalati su un bassorilievo medioevale in marmo dorato e policromo esposto all’esterno
K. Schneider Continua...
Abstract
During the restoration of the facade of the church of S.Pietro Apostolo, Terni, on a bas-rilief of a Christ Pantocrator sculture in white marble placed in the gable of the entrance portal under a compact layer of black incrustation traces of gilding were found. What at first seemed a black crust due to pollution turned out to be several layers of oxalates: the FT-IR analysis showed the presence of calcium oxalate (mainly weddellite: CaC2O4-2H2O)
as well as of gypsum, with traces of silcates, nitrates and calcite. After several trying out several traditional cleaning methods it became evident that they were not suitable to conserve the decorations of the basrelief. Hence a laser based cleaning was tested. During this test beyond the gilding remains of polychrome decorations emerged in various parts of the sculpture. Based on this encouraging results a new project was prepared. The complete surface was cleaned using laser technology using model by EL.EN. S.p.A. that had the following characteristics: laser Vario (preseries) Nd:YAG, λ 1064 nm, LQS, impulse duration 100 ns, energy 50-300 mJ, step 50, Freq. Rip. 20 Hz, with a focus area regolabile between diameter
10 - 0,5 mm. Due to a patient calibration effort of energy, frequenzy and focus area it has been possibile to uncover an astonishing quantity of the original polychrome and gilded finishing. The parameters used were functional to the kind of decoration present on the surface, varying from a minimum impulse of 1,5 mJ/mm2 at 2 Hz (75 mJ on 50 mm2 of surface) for the refinement of the cleaning of the gilded surfaces to a maximum of
9 mJ/mm2 at 15 Hz (250 mJ on 28 mm2 di surface) for the first cleaning of the incrustations on non decorated surfaces. Due to the lack of money no further analysis has been carried out during or after the conservation treatment. The parameters used for cleaning are discussed in detail together with the results, the varies choices made during the treatment, the difficulties encountered and the possibile improvements. The decoration together with the tool marks documented are currently used for a study on the techniques used in the medival sculpture placed in outdoor conditions. Chiudi
p. 131
Coperchio di Sarcofago egizio in arenaria dipinta: considerazioni sugli esiti e sulla messa a confronto di diverse modalitŕ applicative dell’ablazione laser utilizzata per la pulitura
M. Gottardo Continua...
Abstract
In January 2012 the lid of the egyptian coffin in very bad conservative conditions, was transported to the Marble and Casts Studio of the Vatican Museums after a three months storage in a climate-controlled room, in order to obtain stable chemical and physical paramaters. The lid, carved in sandstone, is painted on both sides. At the moment there is no evidence of its origin and conservation events. The topic of this article is the use of laser cleaning for the removal of organic substances previously applied on the painted surface as consolidation and brightening agents, as well as retouching and over-painting. Nd:YAG lasers have been used in QS, LQS, SFR modes, switching the wavelength values through infrared (1064 nm), UV (355 nm) and green (532 nm). The comparison between different parameters led us to select the most appropriate ones with an eye to the conservative profile, especially related to the preservation of the original pigments. Following this method, it was possible to clean the whole surface, especially the most delicate substrate, without the need of pre-consolidation. Chiudi
p. 143
Rimozione laser di ridipinture su scultura in terracotta policroma: il caso della Madonna della Salute di Lobia di Persegara
S. Borella, A. Brunetto, P. Bensi, E. Monni Continua...
Abstract
This paper is about the laser removal made on the cloak of the polychromatic terracotta Madonna della salute. The features of the full size statue date back to the activity of sculptors who worked between Padua and Vicenza in the 16th century. At the beginning the statue was covered with a light and bright glazed coat, in order to reproduce the gravestones' materials. Later it was painted again to adapt to different contexts. Analysis and laboratory diagnosis done with ESEM/EDS and micro-FTIR carried to the identification of at least seventeen coats. Because of the choice to bring back the work of art to the late 19th century chromatism, and because of the deterioration on the cloak of the sculpture, it was hard to obtain results from chemical and mechanical tests. We tested this kind of Nd:YAG (λ=1064 nm) laser in modality SFR (60-120 µs) and LQS (120 ns) to get to the light blue layer.
It was composed by a mixture of calcium carbonate, white of zinc, baryta, Prussian blue, and an oily-origin binder. Chiudi
p. 163
La rimozione di ridipinture a biacca alterate sugli affreschi della cappella di San Lorenzo alla Scala Santa
M.L. Putska, P. Violini, F. Cencia, A. Ferlito, P. Giacomazzi, C. Heineger, F. Leopardi, C. Munzi, G. Pinto, S. Sechi, L. Ugolini Continua...
Abstract
This article deals with the application of cleaning laser technology on the XVI century wall paintings of the Holy Stairs Sanctuary in Rome and, in particular, with the removal of altered re-paintings performed with lead based pigments. During the restoration, the conservators successfully used the EOS QS prototype by El.En. S.p.A. to remove layers of altered lead white that covered up the original painting. Stratigraphic cross-sections were taken before and after the laser treatment and they confirmed that the cleaning technique had not damaged the original painting. However, the altered
re-paintings haven't always been removed. In fact, the complexity of the various painted layers has led the conservators to decide case by case whether to remove, transform, or simply lighten the re-paintings. The implementation of laser technology with the traditional chemical approach, and with an upgraded technique of chemical transformation of dioxide lead, allowed to expand the methodological choices and proved to be a fundamental worksite tool with a remarkable potential. Chiudi
p. 177
Il dipinto murale del Maestro di Figline L’Assunzione della Vergine nella Basilica di Santa Croce a Firenze: pulitura con strumentazione
laser della campitura azzurra del fondo

F. Bandini, I. Barbetti, O. Caruso, A. Felici, C. Frosinini, G. Lanterna, M. Mascalchi, A. Scala, S. Siano Continua...
Abstract
In this paper we present the results of a research project (TEMART) performed during the restoration of the wall paintings depicting the Assumption of the Virgin by the Master of Figline located in the left transept of the Basilica of Santa Croce, carried out by the Opificio delle Pietre Dure. The painting technique and the conservation history have resulted in a state of great fragility of the paint layer requiring, within the work, a specific study on the methods of cleaning the blue color of the background. Cleaning tests were performed using Nd:YAG lasers at different pulse duration and wavelength. The assessment of laser ablation was performed using imaging techniques to different wavelength, X-ray fluorescence (XRF), colorimetric measurements, FT-IR spectroscopy, Dot-ELISA analysis, surveys and stratigraphic X-ray diffraction (XRD). Chiudi
p. 191
Necropoli della Via Triumphalis in Vaticano: applicabilitŕ della tecnologia laser integrata con metodologie tradizionali e biopulitura
R. Giardina, B. Bucciarelli, V. Felici, A. Tagnani Continua...
Abstract
In this paper we present the results of the cleaning of the surfaces with fresco and stucco decorations preserved on the tombs within the archaeological area of Via Triumphalis in Vatican City, describing the different issues tackled and analyzing the integration of laser technology with other methodologies. The necropolis is, today, an hypogeum environment, an archaeological site turned into a museum spread over a steep slope. The conservative and expositive project for the necropolis is supervised by the Department of Greek and Roman Antiquities of the Vatican Museums, directed by Dr. Giandomenico Spinola, with the technical/scientific support of the Diagnostic Laboratory for Conservation and Restoration of the Vatican Museums, directed by Prof. Ulderico Santamaria and his assistant Dr. Fabio Morresi, and the Conservator's Office of the Vatican Museums, directed by Dr. Vittoria Cimino, together with the collaboration of all Restoration Laboratories of the Vatican Museums. The archaeological site, presents a remarkable hygrometric variability which, together with other factors, has led to physical, chemical and biological deterioration of the surfaces. Preliminary tests, constantly accompanied by thorough diagnostic procedures, confirmed that the best strategy was to involve the integration of different cleaning methodologies: chemical, mechanical, bio-cleaning and laser technology. The latter was conducted with Nd:YAG laser 1064 nm with modalities SFR (50-110 µs) known commercially as Smart Clean II , supplied by the company El.En. S.p.A. of Calenzano (Florence). Chiudi
p. 209
Il recupero della decorazione del cubicolo di Lazzaro nelle catacombe di Priscilla: l’inaspettato ciclo di affreschi del IV secolo
M.G. Patrizi, S. Ridolfi, I. Carocci Continua...
Abstract
The decoration of the cubicle of Lazarus, in the Catacombs of Priscilla in Rome, was covered with a layer of limestone concretions very hard to remove and completely darkened, in such a way to cover the underlying painting materials. At the end of a restoration, in1993, investigations of the degradation was executed, the cleaning operation was judged risky and postponed. In 2013, given the excellent results obtained in the cleaning with laser equipments in underground environments, it was decided to use an Nd:YAG laser with an emission at 1064 nm: a Short Free Running laser (pulse duration between 60 µs and 120 µs) and a Long Q-Switched laser (multiple pulse duration of 120 ns). To investigate the nature of the pigments non-destructive X-ray fluorescence (EDXRF) was used over several pigments present in the cubicle. At the end of the work the paintings are again visible and the cubicle is dated to the IV century. Chiudi
p. 227
Trattamento di rimozione laser dalle pitture murali di due arcosoli nella catacomba di Domitilla
A. Brunetto, S. Ridolfi, I. Carocci, B. Mazzei Continua...
Abstract
In this manuscript a work in progress on the mural paintings of the Catacomb of Domitilla in Rome is shown. The mural paintings belong to two arcosoli, opposite one another, along a gallery on the first floor of the Catacomb of Domitilla. The realization of the decoration is dated from the second half of the fourth century. For the quality and complexity of the work, the two units are considered very important and painted by two different artists who most probably became a reference model for the catacomb. On the painted surface several analytical investigations were performed such as the acquisition of microclimatic parameters for the understanding of the dynamics that led to the formation of degradation, multispectral imaging and X-ray fluorescence (EDXRF), FT-IR and micro stratigraphic sections for the definition of the stratigraphy of the art work. The restoration was fulfilled availing of laser cleaning. The laser instruments adopted on different chromatic surfaces are type Nd:YAG, a wavelength of 1064 nm in pulse mode Short Free Running (60-120 µs) and Long Q-Switched (120 ns). Chiudi
p. 245
I cubicola della Villa di Livia a Prima Porta: considerazioni sulla pulitura laser
A. Borzomati, G. Di Gaetano, C. Fiorani, M. Stallone Continua...
Abstract
This contribution describes the wall paintings and the mosaic decorations cleaning phases of the private apartments of the “Villa di Livia” in Prima Porta. The artifacts were in very bad maintenance condition and their usability was limited due to the presence of carbonatic concretions, of manganese oxides and residual materials from previous restoration interventions. The cleaning was made through the usage of mechanical and chemical means that didn't, however, allow the achievement of an optimal level. The laser methodology has permitted the elimination of the last residues of carbonatic layers on the pictorial surfaces and of the manganese oxides from the floor mosaics. Lasers have been used (Nd:YAG) to work at the same wavelength as the nearby infrared (IR) to 1064 nm: Eos 1000 LQS for the wall paintings; QS Thunder Art for the mosaics. The results achieved have been obtained by the usage of both the laser instrumentation together with the most traditional methodologies. Chiudi
p. 265
New advances in laser cleaning research on archaeological copper based alloys: methodology for evaluation of laser treatment
I. Donate-Carretero, J. Barrio MartÍn, M. Cruz Medina-Sanchéz, A.I. Pardo Continua...
Abstract
Previous works have shown promising results on laser cleaning of archaeological metals such as iron, lead, silver and gold. However, the outcomes on copper based alloys are inconsistent. Thus, this article presents the methodology applied, in a research in progress, to assess the laser effects on archaeological copper based samples from three sites of the Iberian Peninsula: Valeria (Cuenca), El Salobral (Albacete) and Calatrava (Ciudad Real). This methodology involves three main stages: first, the definition of working ranges of two Nd:YAG lasers (operating at distinct emission regimes: Short Free Running and Long Q-Switched) and the initial characterization of samples; second, the laser cleaning tests, including the comparison with traditional mechanical methods; and third, the examination of treated surfaces in order to determine the degree of removal, identify the alterations induced by laser irradiation and evaluate the aesthetic appearance of resulting surfaces. Chiudi
p. 279
Valutazione analitica degli effetti di una pulitura laser: la statua in bronzo di Napoleone come Marte Pacificatore di Antonio Canova
A. Sansonetti, M. Colella, P. Letardi, B. Salvadori, J. Striova Continua...
Abstract
The laser cleaning on bronze artefacts is becoming a very promising conservation approach and its wider diffusion would benefit from further studies of effectiveness and harmfulness. Some important references are available still the laser cleaning cannot be considered a traditional method on bronzes surfaces. In this paper, we report on the evaluation of the cleaning tests performed on an important Statue of Napoleon, depicted as Mars the Peacemaker, cast by Righetti in 1811 after a model by Antonio Canova. The sculpture is exposed in outdoor environment in the main courtyard of the Brera Gallery in Milan. The analytical survey on the corrosion products was carried out by means of XRD, µFTIR, µRaman; SEM observations equipped with EDS analyses were accomplished on cross sections. The results put in evidence the ubiquitous presence of brochantite Cu4(SO)4(OH)6. Antlerite Cu3SO4(OH)4 is also present sporadically. Residues of an acrylic, wax treatment (Incralac) and of proteins were highlighted by µFTIR. Laser cleaning tests were carried out with El.En. Combo, both in Long Q-switched (LQS) and Short free running (SFR) regimes. The evaluation of the effects of cleaning was carried out with a portable microscope and a reflectance colorimeter. Moreover a portable FTIR spectrometer was used in order to evaluate the presence of corrosion products after the cleaning. EIS (Electrochemical Impedence Spectroscopy) was used in the field on a selection of the tested areas in order to characterize the effect of laser cleaning on corrosion rate. A specially designed contact probe was used for measurements in the frequency range 100 KHz -10 mHz both before and after cleaning. Chiudi
p. 297
Laser cleaning of archaeological roman glass
M. Cruz Medina-Sanchéz, J. Barrio MartÍn, A. I. Pardo, I. Donate-Carettero Continua...
Abstract
The aim of this paper is to present the results of laser cleaning on a glass bowl as part of its conservation treatment. The object of study is a bowl of glass which was excavated in the Roman necropolis of Sisapo (Ciudad Real, Spain). Its state of conservation was very poor due to the devitrification processes that made the structure extremely fragile and hence the bowl was fragmented into many pieces. The surface was covered with a dense layer of soil deposits and corrosion products that had already penetrated into the external sheets of the damaged glass. The weakness of the glass required an instrument capable of removing the deposits, without putting pressure on the structure or scratching the surface. For that reason we tested the cleaning effects of two Nd:YAG laser devices (λ 1064 nm): SFR and LQS. The effects were very positive especially working with LQS-regime, because the dark layer of deposits absorbed more the laser radiation and it ejected without harming the glass core: as soon as the beam reached the clean layers, the ejection would stop. Chiudi
p. 309
Il restauro della brigantina di Mondragone (CE): la pulitura di un reperto polimaterico con ausilio del laser
M. Musella Continua...
Abstract
Cleaning an object that must be restores probably is the most delicate action to be on it. First it needs to analyze that object by microscope to obtain useful information about the material that constitutes itself, and than the restorer should operate properly the object. The work of “Cleaning” the brigantina armor in Mondragone was the main phase of restoration. The artifact was find out the archeological excavation in Mondragone, it went through six phases, study, searches, macroscopic and microscopic analysis, trial and study of the results in order to seek optimum procedures can be used on it, that it have different materials closing linked. Chiudi
p. 319
L’ausilio del laser per il risanamento di un supporto tessile
I. Negri, F. Zenucchini, T. Cavaleri, A. Piccirillo Continua...
Abstract
This contribution evolves from a master's degree thesis in Conservation and Restoration of Cultural Heritage, from the University of Turin (Academic Year 2012-2013), in agreement with the Centre for Conservation and Restoration La Venaria Reale. The object of the study was the seventeenth-century oil painting on canvas “Madonna and Child with St. Cristina” by Antiveduto Gramatica, which was previously kept in the chapel of King Vittorio Emanuele II in the castle of Moncalieri (Turin). The painting suffered from the presence of three deep cuts on the textile support, which in the past had been restored with patches and heterogeneous adhesives (of protein, polysaccharide, or resinous nature). In order to eliminate the deformation of the substrate caused by the application of the patches, and to proceed to a more functional restoration of the cuts, it was necessary to remove the patches and the stickers that affected the canvas. The work was motivated by the aim to preocede with minimum intervention: the laser cleaning of the substrate occurred only in the areas where the patches were removed. In those areas, the adhesives had completely filled in the texture of the canvas, causing those points to experience a different reaction to the changes in temperature and humidity; this made the restoration of the cuts more difficult. Laser cleaning has been particularly effective in freeing the individual yarns from the adhesives along the lacerations, also when operating on the front of the painting. Before starting the laser cleaning of the canvas, it was decided to compare it with traditional techniques such as mechanical removal with a surgical scalpel after humidification with packs of Agar Agar gel. These methods are ineffective and invasive, as documented by the videomicroscope images. The choice of equipment turned to a Nd:YAG laser operating on a 1064 nm Q-Switched mode, whose effectiveness as part of the cleanup of the verse of the paintings is extensively reported in the scholarship on the field. The extreme thinness of the preparatory layers of the painting demanded that a series of measures was adopted, in order to prevent the interaction between the laser pulse and the paint layers, which are also characterized by white lead and vermilion. Fluences of irradiation are the result of a dual calibration: first, in relation to the resistance of the material that needed to be removed and second, because of the sensitivity of the pigments of the paint film. Chiudi
p. 329
L’impiego della tecnologia laser per la pulitura dei supporti nei dipinti su tavola
M.L. Pustka, M. Alesi, L. Ricciardi Continua...
Abstract
This study addresses the possibility of extending the use of laser technology to the cleaning of the back of panel paintings made on wood. A recent study, completed during the restoration of two paintings in the Vatican Museums collection, revealed the effectiveness of this laser technology. In fact, these two paintings were characterized by wooden supports whose thickness had been reduced. This condition, has allowed us to evaluate the effectiveness of laser technology in the removal of protein substances used as consolidating substance, after the reduction of the thickness of the media. As commonly known, wood is a material very sensitive to thermo-hygrometric variations, able to absorb organic solvents and aqueous solutions during cleaning operations. The wood's sensitivity greatly increases in degraded and fragile paintings for which the laser can be very effective because it allows the surfaces to be cleaned, while avoiding direct contact. The valuable collaboration of the Diagnostic Laboratory for Conservation and Restoration has allowed for a vast campaign of investigations and studies through which it has been possible to develop the correct methodology for the cleaning of paintings on wood. The use of laser and rigid-special gel has allowed us to reduce the stiffness of the boards of wood which caused, together with the old containment systems (often made of fixed iron bars), plastic deformation, cracks, and gaps which affect both the support and the painted surface. Chiudi
p. 341
Intervento di rimozione laser sul manto dorato a rilievo di un dipinto di Carlo Crivelli della Accademia Carrara
A. Brunetto, D. Fagnani, F. Frezzato, G. Valagussa Continua...
Abstract
Intervention by laser was acted in a paint aged to XV century which was made on tempera on table by Carlo Crivelli: Madonna col Bambino. Paint, which is well preserved in both original legend structure and painting surface, was before widely handled in the area of golden relief of Maria. This part of surface was laid of a blue color layer during a previous face-lift, specifically in the concavity of “pastiglia” relief. This layer was composed of protein compounds and terpened resin. Laser instruments were used in this area to recover low golden layers: laser type Nd:YAG (λ 1064 nm) in pulse mode LQS (100 ns) and laser Er:YAG (λ 2940 nm) in time pulse mode Very Short (150 e 250 µs) and Short (450 µs). Removal of repainted area was then operated by laser Nd:YAG, LQS in single mode pulse (130 mJ). Optical UV light investigations were also done, X-ray, reflectography (IR) and false color (IRC), macrophotos of details and filming by digital microscope Dino Lite; two micro samples of golden layer where withdraw for graphic micro layer section by microscopic optical, ESEM–EDS and micro spectral photometry FTIR. Chiudi
p. 355
Rimozione selettiva di resine naturali da due dipinti su tela di Lorenzo Lotto
R. Giardina, U. Santamaria, F. Morresi, F. Persegati Continua...
Abstract
This contribution aims to propose a case in which laser cleaning techniques assisted effectively in the removal of a highly detrimental factor of deterioration of two oil on canvas paintings by Lorenzo Lotto: The Presentation of Jesus in the Temple and The Baptism of Christ, preserved in the Museum of the Santa Casa di Loreto. The two paintings were presenting similar aesthetic /conservative damage, namely a diffusion of stains and splashes of brown color over most of the painted surfaces, which emerged on the paint film during the first phase of cleaning with traditional methodology (chemistry). Accurate diagnostic tests, such as Infrared Spectrometry analysis microFTIR and Pyrolysis, have revealed the oleoresinrelated nature of the substance; for their removal the several solvent-gels selected achieved only limited results, leading to evaluate the applicability of alternative laser based cleaning systems. A first series of micro-tests were focused on the identification of the most suitable laser system, comparing the systems Nd:YAG laser λ 1064 nm mode SFR (50-130 µs) Smart Clean II El.En. S.p.A., and mode QS (8-10 ns) Art Light Laser Lambda Scientifica S.p.A.. A second series of test allowed then to calibrate the operating parameters and select the appropriate gels or filters to shield the pictorial surface and ensure graduality, selectivity and safety conditions necessary to protect the masterpieces. Chiudi
p. 373
La pulitura laser di vernici sintetiche su una tavolozza acrilico-vinilica: rimozione, resistenza e alterazioni
G. De Cesare, P. Iazurlo, P. Biocca Continua...
Abstract
The vinyl-acrylic emulsion paints are an important part of the artistic heritage from the second half of the twentieth century. Due to their sensitivity to organic solvents, useful for the removal of varnish and paint retouching, in the present work the feasibility of selective cleaning by laser has been proven. Most laser instruments available on the market have been employed, such as Er:YAG (λ 2940 nm) and Nd:YAG (λ 1064 nm) at different performances: FR (60-120 µs), LQS (100 ns), QS (6-8 ns). A palette sample of 11 vinyl colors (Polycolor – Maimeri), partly treated with 2 varnish, the acrylic Surfin by Lefranc et Bourgeois and the hydrocarbon Regarlez 1094, was irradiated. The target was to assess the level of risk and ablation threshold of various pictorial films and the ability to remove varnish and the paint without damaging the substrate. The results, macroscopically and microscopically observed in diffused, raking and UV light, suggest a prudent application of these lasers at high fluences. Chiudi
p. 383
Rimozione controllata di ridipinture a olio da dipinti su tela del XX secolo mediante ablazione con laser Nd:YAG (λ 1064 nm) LQS
D. Ciofini, I. Osticioli, A. Pavia, S. Siano Continua...
Abstract
The removal of unwanted overpaintings from 20th century modern paintings represents a very difficult challenge, which usually implies the choice of inefficient treatments, as the use of polar solvents and/or a moderate mechanical actions. The cleaning attempt by traditional methods might be more complicated whether the layer to be removed is much more thicker (more than 50 µm) than the layer underneath and if they were both applied using a lipidbased binder. In such framework, the study is aimed at exploring for the first time the potential of Long Q-Switching Nd:YAG (1064 nm) laser for selective ablation of oil overpaints. Material and laser treatments characterizations were performed by using ESEM-EDX analysis, stratigraphic examinations, portable Raman and Fourier transform infrared (FTIR) spectroscopies. According to the stratigraphy and material composition of the painting to be restored, representative mock-ups were prepared in order to determine the ablation thresholds and optical properties. The parameterization achieved on the mock-ups allowed interpreting and maximizing the selectivity of the laser conservation treatment carried out on the real case. Chiudi
p. 395
Applicazioni laser su spugna marina: le Sculptures-Éponge di Yves Klein
R. Rezza, A. Brunetto, P. Buscaglia, O. Chiantore, T. Poli, A. Rava, M.T. Roberto, F. Zenucchini Continua...
Abstract
The present work concerns Yves Klein's Sculptures-Eponge, made up of natural sea sponges soaked in International Klein Blue, a color invented and patented by the artist composed of artificial Ultramarine Blue and Polyvinylacetate, assembled on metal pedestals. For the purposes of the experimental work, based on cleaning tests, samples were prepared in the laboratory with the same materials and execution technique used by the artist. We realized samples of sponges saturated of IKB and glass slides painted with the same color. The removal from the specimens surfaces of two types of organic substances, one more coherent and adhered to the substrate and one only deposited, was carried out with laser instrumentation. We tested Nd:YAG laser (λ 1064 nm) at three different durations of pulse emission: SFR (60-120 µs), LQS (120 ns) and QS (8 ns). The non-interference with the support and the paint film and the effectiveness of the cleaning operations were monitored through a SEM-EDX microscope and a stereomicroscope. The comparison of the results allowed to define an intervention method which has been applied for the removal of dust deposits and atmospheric particles from a blue sponge conserved in the depository of the Museum of Modern Art in Turin. Chiudi
p. 407
Sperimentazione sull’uso del laser per la pulitura delle piume presenti nella Collezione Etnologica dei Musei Vaticani
S. Pandozy, C. Rivičre, M. Brunori, F. Nepote, A. Rivalta, U. Santamaria, F. Morresi, F. Fraticelli, C. Colantonio, A. Brunetto Continua...
Abstract
The Ethnological Materials Conservation Laboratory, in synergy with the Diagnostic Laboratory for Conservation and Restoration and the Department for Ethnological Collections, is responsible of the conservation of the ethnological collections in the Vatican Museums. Among the materials that comprise the collection, the most delicate and complex are feathers. The cleaning of feathers with traditional methods has some application limits and doesn't always provide satisfactory results. An experimental protocol was defined: the interaction between Nd:YAG laser with a wavelength of 1064 nm and different pulse durations (QS, LQS, SFR) and feather samples that represent all the colours found in nature was methodically studied. All the experimental stages were supported by microscopy shoots, colorimetric measurements, FTIR and SEM investigations. The results of this first experimental stage with QS and LQS modes may be considered satisfactory. The yellowing of some light coloured feathers, steered our research into the use of prototype lasers with picoseconds pulse duration and different wavelengths (532 nm, 694 nm). Chiudi
p. 423
Classificazione di ceramiche archeologiche utilizzando algoritmi neurali applicati a spettri di plasmi indotti da laser (LIBS)
S. Pagnotta, C. Arias, G. Radi, M. Lezzerini, E. Grifoni, S. Legnaioli, G. Lorenzetti, V. Palleschi Continua...
Abstract
The LIBS (Laser-Induced Breakdown Spectroscopy) is a very fast methodology for elemental analysis that can be used in many applications and integrated with other analytical methods. This technique is extremely interesting for archeology as it can be used in situ, without any pretreatment of samples. The results reported in this communication relate to the analysis and classification of 36 ceramic fragments, from Italian Neolithic sites. The samples were analized using the Modě instrument. Considering the high dimensionality of the database, it was necessary to resort to Principal Components Analysis (PCA) to reduce the number of variables which were used as input to algorithms used. This method has allowed to obtain a classification in good agreement with the archaeological classification also providing new details and insights for further analysis. Chiudi
p. 443
La valutazione dei metodi di pulitura per legni monocromi: confronto tra tre sistemi di analisi dei profili superficiali
G. Serra, A. Bortone, D. Vaudan, S. Migliorini, L. Appolonia Continua...
Abstract
It presents the results of the comparison between three different instruments for the assessment of the surface profile, used in order to obtain an objective method of assessing the possible damage on the surface resulting from an act of cleaning of polychrome wooden objects. The approach to a cleaning intervention requires assessment tools able to allow the operator to understand the degree of interaction with the article and consequently, the risk factor intervention. In this context and in order to assess the quality of cleanings with laser compared to other methods more or less on traditional woodwork monochrome, has launched a research program that, at this stage, he had the opportunity to assess what equipment can be used for a microscopic evaluation of surface variations of a material, variations that can be due to interaction of the cleaning methods when these come in direct contact with the surface. The need for comparison of the various methods has required the creation of protocols of recovery which identifies individual areas or zones of measurement, so that the data were repeatable, in order to make a comparison in time and comparable among the various techniques. Chiudi
p. 455
Esempi applicativi della microspia digitale 3D nell’esame di aspetti esecutivi e nella caratterizzazione di trattamenti laser
I. Cacciari, A.A. Mencaglia, S. Siano Continua...
Abstract
The need for observing the microscopic details on artwork surface often happens during the course of the restoration work. Standard optical systems such as eyepieces, videomicroscopes or stereomicroscopes represent powerful helps for the restorer during the examination of the preservation status, the decision of the treatment to be applied and the interpretation of the peculiarity of the decoration process. In recent years there has been an increasing use of digital videomicroscopes due to their low cost and high convenience, but where the observation of the depth is an important element in the assessment, they cannot fully replace the stereomicroscope. The “feeling” of threedimensionality provided by the latter, can allow to understand textural aspects of interest, but in turn it is limited whenever quantitative data on the depth of the surface is needed. In this case, a versatile solution is represented by 3D digital microscopy. Since 2007, our group at IFAC-CNR is directly involved in the development of devices for 3D reconstruction of surfaces mainly based on shape from focusing technique, and now we improve, promote and accelerate the technology transfer to increase the access to this technology [1-6]. Here, after an introduction on the main features of the 3D digital microscopes we have developed, a review of several case studies are presented. These are representative of microrelief problems which can arise in practice in cultural heritage domain. In particular we report the micromorphological studies of the granulation motives decorating Etruscan jewels, the minting toolmarks on Roman coins, the punchworks on Medieval painting, the test of laser cleaning on artifacts. Chiudi
p. 471
Fontana dello Zodiaco a Terni: studio dello stato di conservazione e documentazione mediante laser scanner 3D associato a fotogrammetria
E. Biondi, A. Bovero, M. Demmelbauer Continua...
Abstract
The Zodiac Fountain in Terni is decorated by an extensive stone mosaic made by Corrado Cagli in 1961. Today the artwork is so degraded that the Superintendent is considering a total reconstruction; in order to take this decision in an aware way, has been requested an evaluation of the conservation status at the Centre for Conservation and Restoration of “La Venaria Reale”. A preliminary documentation made with scannerlaser and subsequent photogrammetry, has been a fundamental support to mapping the degradation detected on the site and to represent the information provided by scientific investigations. The acquisition process has been particularly difficult since over a wide area of approximately 100sqm it has maintained a high 3D definition and a correct spatial and colorimetric representation. Specifically, it was necessary to illustrate a extensive cracking
and structural degradation of mortars, as well as an incredible differential thinning of stone tesserae. Chiudi
p. 485
3D model and digital restoration of a medieval gravestone
D. Abate, S. Bruni, V. Greco, G. Maino Continua...
Abstract
The digital or virtual restoration does not act on the art work, but simulates a visual and aesthetic improvement of this one, so enhancing it. It also gives the possibility to choose a series of solutions, before technical operations. Moreover, it is useful to better understand a work of art (both mobile and immobile) or document archives, that for serious reasons of physical degradation cannot be easily restored in the traditional way. In this work we present results of 2D and 3D virtual restoration using open source software, thus proving the efficiency of free codes with respect to more known and generally adopted commercial products. Automatic 3D reconstruction technologies – both active and passive optical devices - have been both applied to the relief and investigation of a Medieval gravestone conserved in the Civico Museo Medievale of Bologna, Italy, representing a noble warrior in his habits. Chiudi
p. 497
Rilievo 3D in ambiente ipogeo con tecniche di image-based modelling e software open source
C. Giancristofaro, E. Grifoni, S. Legnaioli, M. Lezzerini, G. Lorenzetti, L. Marras, S. Pagnotta, V. Palleschi Continua...
Abstract
This paper aims to demonstrate the usefulness of digital reconstructions in the visualisation and interpretation of analytical data obtained in science conservation projects. The study was carried out in the tomb of the monkey, one of the most important tomb of the etruscan necropolis of Poggio Renzo, near chiusi, dated around 480-470 BC. Photogrammetry survey method was used to generate a 3D model of the whole underground grave. The main advantage of this method, which is based on dense stereo matching tools, is the possibility to generate 3D reconstruction starting from a set of uncalibrated images, with non-invasive and easy transportable hardware. Open source software is also used to integrate 3D wall painting data to the diagnostic researches: multispectral analysis1, able to improve the readability of the painted scenes, detecting details otherwise invisible to the human eye, and X-Ray fluorescence2 data that give information on the elemental composition of materials and confirms the behaviour of the multispectral signals collected on the wall painting surfaces. Chiudi
p. 515
Mupris: museum of sarcophagi at the catacombs of Priscilla in Rome, Italy
L. Pecchioli, G. Verdiani, M. Pucci Continua...
Abstract
The basilica of St. Silvestro was erected in 1907 on the foundations of two ancient rooms surrounded by several mausolea, its excavation took place from 1890 to 1906. The presence of some venerated burials led to the realization of a second building thought to be an indoor cemetery. Today the burials and the fragments of sarcophagi have been moved in the museum. Among the choices of project an integrated digital survey both 3D laser scanner that photogrammetry have been used. The survey had to deal with the complex characteristics of the pieces of sculptures and the difficulties linked to the light subsurface dispersion of the marble. To give a better access to monument, an architectural project and the digital technology tried to enhance the real with a digital layer. Chiudi
p. 529
La conoscenza di un bene nel tempo: il pronao della Basilica di Sant’Andrea Apostolo a Mantova
S. Chiarini, S. Cremonesi, L. Fregonese, L. Taffurelli, D. Lattanzi, E. Romoli Continua...
Abstract
It's quite unusual that 3D surveys in Cultural heritage's field, are performed continuously, not only during the designing phase of the restoration, but even during the operative ones. This paper present the collaboration which involved from 2005 to this day the Hesutech group from the “Laboratorio di Ricerca Mantova” of “Politecnico di Milano”, the “Direzione regionale per i beni culturali e paesaggistici della regione Lombardia” and “Diocesi di Mantova”, for the realization of the digital archive of the S. Andrew Cathedral's pronaos in Mantua.The employment of laser scanning and image-based techniques, permit to reduce the aquisitions time, ensuring, quality and high precision. These kind of data can be collected in digital databases from which drawing and 3D models can be extracted, reaching a deep knowledge of the structure, checking the results of event and interventions occurred during its life, as in the case of the earthquake occurred in May 2012. Chiudi
p. 541
Rilievo tridimensionale (laser scanner) dei dipinti murali del Duomo della cittŕ di Amfissa, Grecia
A. Bortot, N. Sartorato, A. Marcolongo, M. Fotini Papakonstandinou, J. Tavlaridis Continua...
Abstract
In the two-year period 2011/2012 a multidisciplinary project of restoration was carried out in the Cathedral of Amfissa (Greece). The interior of the building was decorated through the secco painting technique by the Greek artist Spyros Papaloukas between 1926 and 1931. During the campaign forty scans have been done with 3D laser scanner – in all about five billion of acquired points - with its photos sphere, in order to get a 3D digital point modeling in RGB. Point cloud got behind the ortho pictures extraction of every inner elevation. These pictures allowed a redrawing of paintings in vector. The final scripts have been developed from the usual degradation analysis, by indicating those areas subject to a major level of criticality through photographic details gathered in a final report. The complexity of this case study has allowed us to conceive some useful reflections, in order
to focus on the proper plans of 3D scanner use for survey of painted walls. Chiudi
p. 557
Monitoraggio delle deformazioni del supporto con tecnologie laser e analisi della superficie pittorica con sistemi GIS
L. Baratin, S. Bertozzi, E. Moretti, R. Saccuman Continua...
Abstract
The School of Conservation and Restoration of Cultural Heritage at the University of Urbino, has been developing, for several years, in collaboration with various Public Institutions, the paintings on wooden support research in the field of documentation, 3D survey and management of data through GIS systems. In particular, the 3D survey of the support are obtained with laser scanner technologies and / or systems with 3D reconstruction based on the acquisition of auto calibrated images to obtain a digital model of the surface detected. Of course, the high accuracy and repeatability of the measures taken in monitoring campaigns of time, there where the only visual inspection or photo does not provide sufficient guarantees, will analytically evaluate the possible deformation of providing quantitative data. They compared different systems to verify the accuracy and effectiveness, and the results thus obtained can lead to provide a digital map of work, to be managed later in the complexity of information with GIS systems. Further experimentation in GIS systems is the use of applications that have been adapted to the problems for the analysis of the painted surface. Chiudi
p. 571