Pigment Analyses

Con questo volume, il Centro Internazionale d’Arte e di Cultura di Palazzo
Te prosegue un progetto editoriale iniziato con Indagando Mantegna del
2007, e che, come aveva a suo tempo chiaramente indicato il presidente
Enrico Voceri, “si inserisce pienamente negli obiettivi culturali che da anni
il Centro di Palazzo Te è impegnato a perseguire”. Al pari di allora, il volume
nasce, per così dire, “all’ombra” di una grande esposizione: all’epoca fu
Mantegna a Mantova, nel 2006, oggi è Giovanni Bellini, da poco conclusa
alle Scuderie del Quirinale a Roma. Se ho scelto di virgolettare il termine
“all’ombra”, è perché non vorrei in alcun modo ingenerare equivoci; mostre
e volumi sono stati e sono del tutto indipendenti, ognuno col proprio sapore
particolare, così come un bel fungo nei pressi di un albero; ma, come
è l’albero ad offrire al fungo l’habitat ideale, così le mostre, e la raccolta di
opere in esse contenute, hanno offerto l’occasione di un numero rilevante
di esami scientifici sui dipinti, subito raccolti dal Centro di Palazzo Te.
Come il libro precedente, anche questo porta nel titolo il verbo al gerundio,
Indagando; si vuol trasmettere in tal modo il messaggio di un sapere
che non è scritto una volta per sempre come le tavole della legge, non è
ingabbiato e cristallizzato in sistemi divenuti più rigidi di un cilicio ideologico,
ma “si fa” davanti ai nostri occhi, tentando percorsi nuovi della
ricerca; e può, anzi deve, offrire gli spunti per essere quanto prima superato.
A chi non è addentro ai riti della storia dell’arte, il fatto che siano
possibili, su un unico oggetto, opinioni critiche del tutto diverse e contrastanti
può sembrare frutto o di scarsa professionalità, sempre possibile,
o di qualcosa che somiglia alla magia divinatoria, alla rabdomanzia; ed
è per questo che, in special modo negli ultimi trenta o quarant’anni, si è
fatta sempre più pressante l’esigenza di trovare terreni di discussione che
consentano, se non proprio la replicabilità del dato tipica delle scienze
esatte, almeno una forbice minore di alternative, così che lo statuto della
storia dell’arte divenga più conforme a quello di tali scienze.
(dall'introduzione di Mauro Lucco)

The potential of laser cleaning for paintings as an alternative to traditional cleaning methods has been recognized, and studies using industrial laser equipment have shown some potential. Irradiation at a wavelength of 248 nm has shown to be the most promising for natural resin varnish and overpaint removal, because it is strongly absorbed by triterpenoid varnish functional groups and associated degradation products (Georgiou 1998). However, it has been suggested that a minimal varnish thickness should remain intact to prevent any radiation from being absorbed by the underlying layers. This is because some painting materials have also shown sensitivity to laser radiation (Bordalo 2006). Research into the mechanisms of alterations which may occur due to laser radiation on resins, pigments and oils and its long-term effects has been scarce, and dispersed in its approach because of the multitude of different materials present in the paint layers (Chappé 2003, Sobott 2003, Melessanaki 2006). Thus, the systematic study of laser radiation interaction with paint materials is still important. The aim of this study was to advance the understanding of the effects that KrF excimer laser irradiation has on pigmented oil paint layers.

Abstract Usually referred to as ‘ochre’ or ‘pigment’ in archaeological contexts, ferruginous rocks were commonly exploited during the Later Stone Age in southern Africa. While ochre could lead to crucial inferences about socio-cultural behaviours of past populations, the provenance and the procurement strategies of this material in LSA contexts, as well as its association to rock art remain largely understudied. In the present study, seventeen ochre sources from five geological zones in north-central Namibia and 41 archaeological ochre pieces discovered in the stratigraphic sequence of the Later Stone Age site of Leopard Cave, Erongo Mountains - Namibia, were analysed by ICP-OES and ICP-MS/MS. Geochemical data coupled to data pre-treatment considerations and multivariate statistical analyses demonstrate that archaeological ochres were both collected locally and regionally from more distant sources. Beyond shedding new light on ochre provenance for rock art in north-central Namibia during the Later Stone Age, our data provide new insight into the mobility of past populations and the interactions existing between distinct rock art areas in north-central Namibia.

This study concerns the investigation of mortar layers and pigments of wall paintings from the Roman town of Emona (Ljubljana, Slovenia). Fragments of wall paintings consist of up to three preserved mortar layers. The mineralogical–petrographic compositions of the mortars were determined by means of optical microscopy and FT–IR spectroscopy. The investigated samples were divided into several groups based on similar thicknesses of the mortar layer, the binder colour and the composition of an aggregate. Furthermore, the results of mercury intrusion porosimetry showed that mortar layers consisting of carbonate grains exhibited lower porosity with respect to layers with mainly silicate grains, which is attributed to the angular shapes of carbonate aggregate. This is in accordance with the drilling resistance measurement system test (DRMS), confirming that layers with angular carbonate grains are harder than those with addition of rounded silicate ones, due to the good packing effect. The wall paintings were mainly executed using the fresco technique, while for some details secco was used. The identified pigments were red and yellow ochre, green earth, Egyptian blue, carbon black and lime white; all of them belonged to the so-called austere pigment, which is quite common in Roman wall paintings.

Throughout history, Iranian painting has encountered heterogeneous cultures and traditions of the East and West. The Iranian painters showed everything with the simplest lines and the purest colors, which seems convincing, and in contrast to the period of the adaptation of Western traditions, there is no sign of naturalism in Iranian paintings. In Iran, one of the most impressive period of wall painting decoration was 15th century Qajar period. In this period, style of Qajar paintings includes the combination of wall painting style in the Safavid period and classical European painting. At the beginning of Qajar period Iranian source is more, in the middle of Qajar period. At the end of this period, the influence of the European style becomes more dominant on Iranian paintings. In Qajar period, even the baths were also covered with wall paintings. In this study, one of the best example of bath, Shah Bath, was searched in terms of architectural, historical, archaeological, material characteristics and their deterioration problems. In addition the chemical analyses has been applied to the wall paintings for the determination of type of pigments. The wall paintings were also determined in terms of construction techniques. As a result, the source of damages of the mentioned paintings which happened because of different factors and their effects on the painting were discussed. Özet Tarih boyunca İran resmi, Doğu ve Batı'nın heterojen kültürleri ve gelenekleriyle karşılaştı. İranlı ressamlar, her şeyi en basit çizgilerle ve ikna edici görünen en saf renklerle gösteriyorlardı ve Batı geleneklerinin adaptasyon döneminin aksine, İran resimlerinde naturalizmin belirtisi yoktu. İran'da, duvar resmi dekorasyonunun en etkileyici dönemlerinden biri, 15. yüzyıl Kaçar dönemi idi. Bu dönem, Qajar duvar resimlerinin tarzı, hem Safavi döneminin hem de klasik Avrupa resminin birleşimini içerir. Kaçar döneminin başında İran etkisi, Kaçar döneminin ortasında ise Avrupa etkisi daha fazladır. Bu sürecin sonunda, Avrupa resim stilinin etkisi İran resmi üzerinde daha baskın bir hale geldi. Kaçar döneminde hamamlar bile duvar resimleriyle kaplandı. Bu çalışamada, bu dönemin hamamların en güzel örneklerinden biri olan Şah Hamamı mimari, tarihi, arkeolojik, maddi özellikler ve bozulma sorunları açısından incelenmiştir. Bununla beraber, duvar resimlerinin pigment türlerinin belirlenmesine yönelik olarak kimyasal analizler de uygulanmıştır. Ayrıca duvar resimleri yapım teknikleri açısından da incelenmiştir. Sonuç olarak, söz konusu duvar resimlerinin bozulmalarının kaynağı ve farklı nedenlerden kaynaklanan zararları ile resimler üzerindeki etkileri değerlendirilmiştir.

F.F. Runge's 'Grundriß der Chemie' was one of the most popular books written in German on the fundamentals of chemistry in the 19th century. It contains no chemical formula or equitations; instead, the author illustrated the explanations of chemical compounds and reactions with samples of the described compounds. The poster shows first results of the chemical analyses of those samples.

Usually referred to as 'ochre' or 'pigment' in archaeological contexts, ferruginous rocks were commonly exploited during the Later Stone Age in southern Africa. While ochre could lead to crucial inferences about socio-cultural behaviours of past populations, the provenance and the procurement strategies of this material in LSA contexts, as well as its association to rock art remain largely understudied. In the present study, seventeen ochre sources from five geological zones in north-central Namibia and 41 archaeological ochre pieces discovered in the stratigraphic sequence of the Later Stone Age site of Leopard Cave, Erongo Mountains-Namibia, were analysed by ICP-OES and ICP-MS/MS. Geochemical data coupled to data pre-treatment considerations and multivariate statistical analyses demonstrate that archaeological ochres were both collected locally and regionally from more distant sources. Beyond shedding new light on ochre provenance for rock art in north-central Nami...