1,720,970 research outputs found
Dipinti sottoposti a foderatura: lo stato di conservazione
Full text linkSei dipinti (opere di E. Tito, F.P. Michetti, A. Mancini, G. Sacheri, E.Rizzi) della Galleria d'Arte Moderna Ricci Oddi di Piacenza sono stati studiati, in quanto presentavano delle problematiche conservative, dovute ad un peggioramento dell'adesione degli strati pittorici e della preparazione dal supporto. Tale fenomeno è stato osservato in particolar modo su alcune opere sottoposte in passato ad interventi di foderatura.
L'obiettivo del lavoro è stato quello di valutare quanto la foderatura possa avere contribuito a determinare le problematiche conservative riscontrate, in relazione alle caratteristiche del supporto tessile, al tipo e alla spessore dello strato preparatorio, al tipo di legante organico utilizzato nel film pittorico e pigmenti, considerando anche l'aspetto ambientale (interazione tra materiali e condizioni di temperatura ed umidità presenti nella galleria). A tal fine si è considerato fondamentale intervenire con una campagna di indagini scientifiche volte alla caratterizzazione dell'adesivo, della tecnica pittorica, del tipo d fibra presente nelle tele.
In particolare, questo studio riporta le indagini volte a verificare la presenza di colla pasta, colla d'amido o colla animale, attraverso la caratterizzazione chimico-fisica dell'adesivo. A tal fine, sono stati prelevati campioni dalla tela risvoltata nel retro del telaio, ed effettuate indagini mediante spettroscopia FT-IR; Test con reattivo di Lugol, gascromatografia accoppiata alla spettrometria di massa (GC-MS).
I risultati delle indagini effettuate hanno indicato la presenza di una colla mista (colla d'amido e colla animale) nei campioni prelevati dalla tela di foderatura
Di sana e robusta Costituzione? Indagini biologiche e ambientali su e “attorno” la copia originale della Costituzione Italiana, conservata presso l’Archivio Centrale dello Stato a Roma
Full text linkla copia originale della Costituzione Italiana si trova all'interno di una cassaforte
metallica al secondo piano di un ala dell'Archivio Centrale dello Stato all'EUR, Roma, in un locale ad uso ufficio, frequentato stabilmente da impiegati amministrativi. Il faldone, contenente altri documenti storici,è stato esaminato da un restauratore professionistain tutte le sue parti con l'aiutodi un microscopio digitale 50-200x a lucebianca e NUV. dimostratoLe analisi microbiologiche hanno dimostrato l'assenza di attività biologica sulle pagineche compongono la copia originale della Costituzione italiana.Alcune tracce di attacchi biologici sonostate invece riscontrate con l'aiuto del microscopio ottico ed elettronico a scansione in corrispondenza di macchie di foxing presenti su documenti conservati nello stesso faldone in cui è conservato il manufatto, tuttavia le analisi colturali non hanno rilevatola presenza di propaguli microbici vitali.Il foxing di natura biologica infatti è solitamente un effetto tardivo di un attacco biologico condotto da funghi xerofili specializzati, i cui resti interagendo con alcuni componenti endogeni della carta e con inquinanti
esogeni portano alla formazionedelle macchie color ruggine
Studio archeometrico dei dipinti murali di Spyros Papaloukas nel Duomo di Amfissa in Grecia
Full text linkIl Duomo della città di Amfissa (Grecia) è stato costruito nel periodo 1859 – 1869. L’interno del Duomo è stato dipinto interamente dal pittore greco Spyros Papaloukas (1927 – 1932). Lo stato di conservazione della superfice dipinta attualmente versa in condizioni molto precarie ed in vista di un profondo intervento di risanamento e restauro e stata intrapresa una approfondita indagine diagnostica delle superfici dipinte. Allo scopo sono stati avviate una serie di controlli analitici e tecnologici. Nel caso degli intonaci dipinti, particolare attenzione è stata dedicata agli strati pittorici, alla composizione degli strati preparatori, alla caratterizzazione delle malte e ai problemi di deterioramento ad esse connesse. Frammenti di materiale pittorico sono stati analizzati mediante gascromatografia/spettrometria di massa per la ricerca dei leganti organici. E’ stato osservato materiale organico in tutti i campioni, in particolare olio di lino invecchiato e uovo. Dai dati analitici e dalle osservazioni in situ si ritiene che la particolarità dell’opera sia che l’intera superficie (1.500 m2 di superficie) sia stata dipinta con la tecnica pittorica murale “a secco”, adoperando esclusivamente dei leganti organici. Il quadro generale dei risultati delle indagini sui materiali inorganici insieme allo studio dei leganti organici ha rappresentato la base di riferimento per una mirata progettazione dell’ intervento conservativo necessario.
Il presente lavoro fa parte del “International Multidisciplinary Conservation Project of the Holy Mary Annunciation Metropolitan Church of Amfissa (Greece)”
Caratterizzazione dei materiali pittorici e dei materiali impiegati nei precedenti restauri del telero di VITTORE CARPACCIO RAFFIGURANTE L’ARRIVO A COLONIA
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Paper preservation with polyamidoamines: a preliminary study
No full textThis research deals with the use of water soluble polyamidoamines (PAAOH’s) as innovative paper preservatives endowed with deacidification and biostatic properties. They were obtained by reaction of N,N-methylenbisacrylamide (MBA) with ethanolamine (EA) and were characterized by Fourier Transform Infrared Spectroscopy analysis (FTIR), Electrospray Mass Spectrometry (ESI-MS) and Nuclear Magnetic Resonance (NMR). PAAOH’s should tightly bind to cellulose through a network of H-bonds, as suggested by molecular mechanics calculations. Actually, FTIR analysis and the increment in anhydrous mass of paper samples demonstrated that PAAOH’s were progressively absorbed by paper cellulose without altering the original color of paper as observed by colorimetric analysis. The deacidifying effects were confirmed by significant increment in pH values of paper after treatment in comparison to the untreated paper samples. In vitro antibiogram assay showed a good but variable biostatic effect on different fungal test strains, depending by species, PAAOH’s concentration and pH in the substrate
An evaluation of changes induced by wet cleaning treatments in the mechanical properties of paper artworks
Full text linkWet cleaning of ancient papers is a
common treatment performed for the removal of
degradation products, external contaminants and salts,
which can promote the degradation of cellulose (i.e.,
hydrolysis, oxidation). In this research, the effects on
the mechanical properties of paper samples caused by
wet cleaning treatments were evaluated by considering
the changes induced in the ultimate tensile
strength, deformation at break and flexibility. For this
purpose, samples were subjected to different aqueous
cleaning treatments such as immersion in deionised
water and the application of rigid gels of agar and
gellan gum at different concentrations was carried out.
Tensile tests were run, and morphological observations
of paper by means of light microscopy and
scanning electron microscopy were recorded. Contrary
to the significant changes in the mechanical
properties of paper samples after immersion treatment
(an increase in flexibility as the elongation at break),
the use of gelled systems caused slight improvement in
the mechanical properties of paper (in both the
ultimate tensile strength as well as in the breaking
strain). Changes in the mechanical properties of paper
were also correlated with slight changes in the
diameter of the cellulose fibres as a consequence of
the swelling action of water molecules, especially in
the case of immersion treatment. Finally, the tensile
tests performed on the paper samples after thermohygrometric
accelerated artificial ageing (70 C and
65 % RH) demonstrated that cleaning treatments by
rigid gels did not seem to accelerate any sort of paper
degradation in the mid to long term
Chemical physical characterization of ancient paper with functionalized polyamidoamines (PAAs)
No full textHybrid inorganic–organic treatments,
based on amide-amine polymers (PAAs), against
thermal oxidation have been prepared on paper dating
back to eighteenth century. The polymeric sols are
obtained by step-growth Michael addition polymerization
and functionalized with siloxane network by
sol–gel method. Five types of samples have been
prepared changing the molar ratios among the reagents
and their concentration. The treated paper samples
were subjected to morphological and structural characterization,
by using Scanning Electron Microscopy
and vibrational spectroscopies (FTIR and Raman),
respectively. Static mechanical tests have been carried
out on the samples for measuring elastic modulus,
ultimate strength, ultimate deformation and energy
loss, whereas dynamic-mechanical measurements
have been recorded at increasing temperatures to
evaluate E0, E00 and tan d. Finally, Thermo-Gravimetry and Differential Scanning Calorimetry have been
carried out in order to study the behaviour of treated
samples in temperature with respect the plain paper.
The main result is that the siloxane-modified PAA
treatment can improve significantly both mechanical
and dynamic-mechanical properties, as well as the
thermal resistance, without altering the aspect and
texture of the original material. In general, the thicker
the impregnation, the better the performances of
treated paper: the thickest treatment is able to prevent
the combustion of paper samples until 500 °C. The
treatment is very promising to preserve ancient
manuscripts during accidental fire and against the
embrittlement due to natural ageing
The use of polysaccharide rigid gels in cleaning treatments : multi analytical approach for the study of their performance, effectiveness and interference with paper artworks
No full textThe cleaning of paper artworks represents a fundamental treatment since external contaminants, metals, spores, etc. can promote degradation of cellulose (the principal constituent of paper). For this reason the removal of such components may partially preserve paper over time. Different cleaning treatments can be applied on paper artworks, for instance dried methods, aqueous cleaning systems. Recently polysaccharide rigid hydrogels (i.e: Agar and Gellan gum) have been used for the cleaning of paper, in order to increase surface wettability of paper and control the diffusion of water molecules in paper. This aspect represents an advantage especially in case of delicate surfaces and in presence of hydrophilic graphic media. The use of water (in a free or gelled form) may promote the extraction of hydrophilic components (either degradation products or original constituents of paper). Therefore the evaluation of the extraction of original constituents of paper induced by cleaning treatments as well as the evaluation of the effects of cleaning on chemical-physical properties of paper represents a relevant aspect in the context of paper conservation. For this reason the aim of the research is the evaluation of the extraction of sizing agents as gelatine contained in paper, products of hydrolysis of hemicelluloses and cellulose, induced by aqueous cleaning treatments and the evaluation of the effects of the cleaning on morphological, mechanical properties of paper. The study is carried out on paper artworks of different periods (from XVI to XX century) subjected to cleaning by immersion in distilled water and to application of Agar and Gellan gum rigid gels. GC-MS analysis show that such cleaning treatments can cause the extraction of products of hydrolysis of hemicelluloses and cellulose as well as the extraction of gelatine. This phenomenon is more evident in the case of the immersion of paper in distilled water and may partially explain the significant variation in the mechanical properties of paper observed by means of tensile testing after cleaning. In fact paper samples subjected to cleaning by immersion show a relevant decrease in the Ultimate Tensile Strength, probably correlated to the evident extraction of water in the free form of hemicelluloses products, and a relevant increase in the breaking strain (probably caused by the swelling of cellulose and the formation of hydrogen bonds between cellulose chains and water molecules). Such effect is reduced and a moderate improvement in mechanical properties of paper is observed when polysaccharide rigid gels are used.
The application of rigid gel for the cleaning of ancient paper seems to be respectful of the original surface morphology of paper as well as in the case of the immersion treatment as revealed by 3D profilometer analysis and observation by stereo-microscope and SEM-EDS. On the contrary the application of dried methods (i.e.: wishab sponge) and cellulose ethers by means of cotton swabs, etc. may promote defibration and alteration in the morphology of paper surface because of the mechanical action induced by such applications. An analytical evaluation of the residues left by gels on paper after cleaning treatments is carried out by means of GC-MS analysis. Results show a reduced presence of gels residues left on paper only in the case of the application of 1% gel, because of its soft consistence and its difficult manipulation.
The results obtained in this research demonstrate that the effects of cleaning are strongly dependent on the type of paper, its papermaking, its conservation and for this reason the choice of the most suitable method of cleaning should consider materials present in paper and properties of paper. For this reason chemical-physical analysis could be of great help for the knowledge of materials in paper and for the monitoring of cleaning treatments
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