Mostra Internazionale dell’Artigianato a Firenze


intro_articolo_tibet

Il primo pensiero va al Tibet, ospite d’onore 2015, per la tragedia subita

http://www.mostraartigianato.it/it/home-page-it/7-la-fiera/331-tibet-ospite-d-onore-2015.html

 

Ancora pochi giorni…fino a domenica  3 maggio, l’occasione per osservare alcuni aspetti di tanti mondi e culture…intervenite numerosi e venite a trovarci!  :-)

Istituto per l’Arte e il Restauro “Palazzo Spinelli” Firenze

Il restauro è passione e come tale è meraviglioso viverlo e condividerlo…

http://www.palazzospinelli.org/ita/channel-view.asp?id=podcast&idn=424

 

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Making a Karibari Board


Nella conservazione, l’essiccazione o l’umidificazione della carta pone sfide particolari quando le caratteristiche dimensionali e visive della carta originale devono essere conservate. A causa di questo, l’essiccazione di un artefatto è un passo fondamentale nel suo trattamento. Ci sono una serie di tecniche di essiccazione della carta dalle quali il conservatore può selezionare e adattare allo specifico caso, la metodologia più consona, allo scopo di migliorare il risultato di ogni trattamento.

La tradizionale  tavola Karibari giapponese è un tipo di pannello di essiccazione che può essere utilizzato in questo processo (Karibari in giapponese significa montatura temporanea). La tavola Karibari controlla e rallenta la velocità di essiccazione, mantenendo il manufatto in tensione sul telaio. I conservatori di carta usano la loro valutazione e la loro esperienza per scegliere la tecnica di essiccazione più appropriata per il supporto cartaceo specifico e applicarla su di esso.

Lo scorso gennaio abbiamo deciso di costruire la nostra tavola Karibari grazie all’esperienza avuta dopo la nostra visita all’ allievo di conservazione Hsiu-Mei Huang di Taiwan. In sette giorni, abbiamo selezionato, tagliato e incollato carta di gelso giapponese di spessore variabile su un pannello in legno e lasciato asciugare ogni strato  per un giorno intero prima di procedere al livello successivo. Non appena iniziato l’intenso lavoro di costruzione della tavola Karibari, abbiamo pensato che sarebbe stato interessante documentarne il processo. Il primo giorno il fotografo locale Zacarias Garcia fu invitato a far visita al laboratorio di conservazione, e subito ci siamo resi conto che un video sarebbe stato il  miglior mezzo per mostrare il nostro lavoro.

Il documentario qui incorporato  (e disponibile sul canale YouTube di Folger ) mostra il processo che abbiamo attraversato nella costruzione della tavola, insieme con il commento di Andrew Hare, Conservatore di Vigilanza della pittura dell’Asia orientale, Studio di Conservazione  alla Freer Galleria d’Arte del Smithsonian Institution e alla Galleria d’Arte Arthur M. Sackler.

http://collation.folger.edu/2014/05/making-a-karibari-board/

karibari

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Progetto “Itinerari di scienza alle Terme di Montecatini”


Manifesto Montecatini0001

 

Si è svolta nel mese di giugno una stimolante esperienza in collaborazione con il Liceo “Coluccio Salutati” di Montecatini Terme.

Dopo due giornate teoriche di introduzione alle principali metodologie applicate al restauro cartaceo e membranaceo, svoltesi presso l’Istituto, ho avuto il piacere di aprire il mio laboratorio ai ragazzi del terzo anno del Liceo. Per una settimana, gli allievi, sotto la mia supervisione, hanno affrontato le fasi basilari per un restauro conservativo di documenti cartacei a stampa. Dallo smontaggio alla cartulazione, dalla pulitura meccanica al test di solubilità degli inchiostri, dal test di rilevazione del Ph alle operazioni per via umida, quali il lavaggio e la deacidificazione, la ricollatura, l’asciugatura e la spianatura. Per ultimo, ma non meno importante, hanno provato ad operare risarcimenti di lacune e strappi mediante l’ausilio di carte e veli giapponesi, fabbricati manualmente secondo l’antica tradizione cartaria.

All’interno del progetto era previsto l’intervento conservativo su alcuni volumi antichi della Biblioteca delle Terme, sotto la supervisione dei Beni Librari della Regione Toscana.

Esperienza multidisciplinare che sta per concludersi con successo e che verrà presentata a livello cittadino con una esposizione pubblica.

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Making Colour: un viaggio fra arte e scienza


<em>The Natural System of Colours</em> di Moses Harris<br />1769/1776<br /><br />Il cerchio "prismatico" dipinto da Harris mostra in che modo si possono ottenere i colori a partire dai colori primari rosso, giallo e blu, posti sul primo cerchio. I colori intermedi fra i tre primari formano la base del secondo cerchio cerchio, e così via. I triangoli al centro mostrano come nella miscelazione sottrattiva dei colori (quella dei colori riflessi) il nero risulta dalla sovrapposizione dei tre colori primari. <br /><br />Credit: Royal Academy of Arts, London

The Natural System of Colour di   Moses Harris
1769/1776

Il cerchio “prismatico” dipinto da Harris mostra in che modo si possono ottenere i colori a partire dai colori primari rosso, giallo e blu, posti sul primo cerchio. I colori intermedi fra i tre primari formano la base del secondo cerchio cerchio, e così via. I triangoli al centro mostrano come nella miscelazione sottrattiva dei colori (quella dei colori riflessi) il nero risulta dalla sovrapposizione dei tre colori primari. 

Credit: Royal Academy of Arts, London

Un affascinante viaggio fra arte e scienza è quello proposto dalla mostra Making Colour allestita presso la National Gallery di Londra, che resterà aperta al pubblico fino al prossimo 7 settembre. 

Ripercorrendo secoli di storia dell’arte, dal primo Rinascimento fino al movimento impressionista, la mostra illustra il modo in cui gli artisti delle varie epoche ottenevano gli effetti cromatici dei loro dipinti e i materiali che usavano per creare i pigmenti, dalle prime tinte ottenute schiacciando insetti fino ai moderni colori di sintesi. 

L’esposizione è articolata in una serie di sale dedicate ai vari colori, arricchite di dipinti tessuti, ceramiche, vetri, campioni di minerali e postazioni interattive che aiutano a penetrare i segreti dei maestri del colore e a comprendere la prospettiva scientifica sul colore e la sua percezione.

http://www.lescienze.it/news/2014/07/19/foto/colori_dipinti_making_colours-2217257/1/#1

Interessante! Da non perdere :-)

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Declaration of Independence


Importanti documenti conservati negli Archivi!

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Making Manuscripts


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Characterization and Identification of Colorants in a Japanese Pillar Print


Traditional colorants used in Japanese woodblock printing may be visually and chemically altered by exposure to light, pollutants, pH extremes, humidity, water, and other solvents. It is helpful, therefore, to identify colorants in Japanese prints when considering the potential impact of conservation treatment, storage, and exhibition on their long-term preservation.

Overall before treatment.           Before Conservation Treatment
Torii Kiyonaga (1752-1815), Ouka No Nibijin
(Two Beauties under a Cherry Tree), 1782-3,
color woodblock print on Japanese paper,
Library of Congress FP 2 – JPD, no. 530.

Detail of five printing ink colors.

Detail of the five ink colors present in the print.

Method

Five colored inks, including black, were used to create “Two Beauties under a Cherry Tree” (Ouka no nibijin), printed by Torii Kiyonaga in 1782-83. The inks were identified by close visual inspection and non-destructive instrumental analysis. First, a stereomicroscope at high magnification was used to visually determine if the inks appeared to be composed of dyes, pigments, or a mixture of the two. When pigment particles were present, physical characteristics such as relative particle size, edge definition, surface reflectance (matte or shiny), and transparency or opacity were noted. These observations were compared to known samples of traditional Japanese colorants to make a tentative identification. For example, the green robe on the figure at the right is a mixture of blue and yellow pigments. The yellow pigment is semi-opaque, irregularly shaped, and — compared with the blue pigment particles, which were small enough to sink into the interstices of the paper — much larger and variable in size. The yellow pigment correlated well with known samples of orpiment, an arsenic sulfide pigment, and the blue appeared similar to indigo, a plant based dye.

Green colorant under five times magnification showing yellow and blue colorant particles.

Green colorant under five times magnification showing yellow and blue colorant particles.

Imaging under discrete bands of ultraviolet, visible, and infrared radiation using a multispectral digital camera was used to further characterize the colorants. Because each colorant is a different chemical compound, each selectively absorbs, fluoresces, transmits, or reflects characteristic wavelengths when exposed to specific bands of the electromagnetic spectrum. These characteristic responses are captured by the digital camera and are compared to the spectral responses of known colorant samples. Because different materials may have similar responses to all wavelengths and therefore cannot be readily distinguished by imaging alone, additional analytical tools are often used to solidify a preliminary identification.

Eight images obtained from the multispectral camera.

Multispectral imaging showing differing spectral responses to discrete bands of radiation. Clockwise from Top Left: Visible (400-700 nm); Ultraviolet-induced visible fluorescence (300-400 nm); Ultraviolet reflectance (300-400 nm); False color ultraviolet; Near infrared 1 (700-950 nm); Near infrared 2 (1000-1100 nm); False color near infrared 1; False color near infrared 2.

Conclusions

 

Comparison of the spectral responses obtained from the print with known samples, supported by instrumental analyses provided by the Preservation Research and Testing Division, indicated that the printing inks are composed of:

Red lead: an orange-red mineral pigment known in Japan as tan. Red lead absorbs ultraviolet radiation (appears dark in the ultraviolet images), is transparent to infrared (disappears in the infrared images), and appears yellow in false-color infrared. The chemical compound of red lead, lead tetroxide, degrades to a black product, lead sulfide, upon exposure to sulfurous compounds. In false-color infrared, the black corrosion product, lead sulfide, appears dark. (While the presence of lead sulfide could be the result of exposure to sulfur dioxide, an omnipresent environmental pollutant produced by burning fossil fuels, Japanese printmakers sometimes deliberately induced conversion of red lead tetroxide to silver lead sulfide, which also degrades to a black color. For more information about both environmentally-induced and deliberate alteration of red lead in Japanese prints, see Conservation Treatment of a Japanese Pillar Print.) X-ray fluorescence (XRF) analysis confirmed the presence of lead in the red colorant of the Kiyonaga print and Raman spectroscopic analysis positively identified the colorant as red lead.

Safflower: a pink colorant extracted from safflower petals, known in Japan as beni. The most characteristic feature of beni is its bright orange-pink fluorescence when exposed to ultraviolet radiation. Beni fades quickly upon exposure to light and may be easily solubilized in water. XRF and Raman analyses indicated only that the pink colorant in the Kiyonaga print is organic. A definitive identification of the colorant would require further analysis. The presence of safflower was indicated primarily through its bright, orange-pink fluorescence in ultraviolet light.

Indigo: a dark blue plant-based dye precipitated onto an inorganic substrate such as a metallic salt, known in Japan as bero-ai. In the image by Kiyonaga, indigo was used to print the textile pattern in the kimono worn by the left figure and was mixed with yellow to create green, seen in the kimono worn by the right figure. The colorant has altered over time so that it appears a dull green-gray. The most characteristic feature of indigo is its bright pink appearance in false-color infrared. Indigo is sensitive to high pH. Raman spectroscopy positively identified the gray colorant in the Kiyonaga print as indigo.

Orpiment: an opaque mineral pigment composed of arsenic sulfide, known as shio. The spectral responses of the yellow colorant, used alone and mixed with blue to create green, was similar to known samples of both orpiment and gamboge. However, as noted during examination under the stereomicroscope, the physical characteristics of the pigment appeared more similar to orpiment than to gamboge, a colorant obtained from tree resin that is valued for its brilliant yellow hue and transparency. XRF confirmed the presence of arsenic and sulfur in the yellow colorant of the Kiyonaga print. Raman spectroscopy positively identified the colorant as orpiment.

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VANISHING DA VINCI


Studying a famous Leonardo self-portrait, a team of scientists has developed a new, nondestructive way to gauge degradation of ancient paper art and docs.

This is Leonardo da Vinci's self-portrait as acquired during diagnostic studies carried out at the Central Institute for the Restoration of Archival and Library Heritage in Rome, Italy. Credit: M. C. Misiti/Central Institute for the Restoration of Archival and Library Heritage, Rome

One of Leonardo da Vinci’s masterpieces, drawn in red chalk on paper during the early 1500s and widely believed to be a self-portrait, is in extremely poor condition. Centuries of exposure to humid storage conditions or a closed environment has led to widespread and localized yellowing and browning of the paper, which is reducing the contrast between the colors of chalk and paper and substantially diminishing the visibility of the drawing.

A group of researchers from Italy and Poland with expertise in paper degradation mechanisms was tasked with determining whether the degradation process has now slowed with appropriate conservation conditions — or if the aging process is continuing at an unacceptable rate.

To do this, as they describe in Applied Physics Letters, from AIP Publishing, the team developed an approach to nondestructively identify and quantify the concentration of light-absorbing molecules known as chromophores in ancient paper, the culprit behind the “yellowing” of the cellulose within ancient documents and works of art.

“During the centuries, the combined actions of light, heat, moisture, metallic and acidic impurities, and pollutant gases modify the white color of ancient paper’s main component: cellulose,” explained Joanna Łojewska, a professor in the Department of Chemistry at Jagiellonian University in Krakow, Poland. “This phenomenon is known as ‘yellowing,’ which causes severe damage and negatively affects the aesthetic enjoyment of ancient art works on paper.”

Chromophores are the key to understanding the visual degradation process because they are among the chemical products developed by oxidation during aging and are, ultimately, behind the “yellowing” within cellulose. Yellowing occurs when “chromophores within cellulose absorb the violet and blue range of visible light and largely scatter the yellow and red portions — resulting in the characteristic yellow-brown hue,” said Olivia Pulci, a professor in the Physics Department at the University of Rome Tor Vergata.

To determine the degradation rate of Leonardo’s self-portrait, the team created a nondestructive approach that centers on identifying and quantifying the concentration of chromophores within paper. It involves using a reflectance spectroscopy setup to obtain optical reflectance spectra of paper samples in the near-infrared, visible, and near-ultraviolet wavelength ranges.

Once reflectance data is gathered, the optical absorption spectrum of cellulose fibers that form the sheet of paper can be calculated using special spectroscopic data analysis.

Then, computational simulations based on quantum mechanics — in particular, Time-Dependent Density Functional Theory, which plays a key role in studying optical properties in theoretical condensed matter physics — are tapped to calculate the optical absorption spectrum of chromophores in cellulose.

“Using our approach, we were able to evaluate the state of degradation of Leonardo da Vinci’s self-portrait and other paper specimens from ancient books dating from the 15th century,” said Adriano Mosca Conte, a researcher at the University of Rome Tor Vergata. “By comparing the results of ancient papers with those of artificially aged samples, we gained significant insights into the environmental conditions in which Leonardo da Vinci’s self-portrait was stored during its lifetime.”

Their work revealed that the type of chromophores present in Leonardo’s self portrait are “similar to those found in ancient and modern paper samples aged in extremely humid conditions or within a closed environment, which agrees with its documented history,” said Mauro Missori, a researcher at the Institute for Complex Systems, CNR, in Rome, Italy.

One of the most significant implications of their work is that the state of degradation of ancient paper can be measured and quantified by evaluation of the concentrations of chromophores in cellulose fibers. “The periodic repetition of our approach is fundamental to establishing the formation rate of chromophores within the self-portrait. Now our approach can serve as a precious tool to preserve and save not only this invaluable work of art, but others as well,” Conte noted.

American Institute of Physics

http://www.heritagedaily.com/2014/06/vanishing-da-vinci/103502

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Jacson Pollock’s “Mural”


The Getty Conservation Institute and the J. Paul Getty Museum embarked on a two-year project of conservation and research on Jackson Pollock’s seminal work Mural (1943). This included investigation into the materials and techniques used by Pollock during this critical early moment in his career, and a major conservation treatment to improve the painting’s aesthetic impact and to stabilize its physical structure.

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