早期失效保护修复材料对壁画的影响

现存的馆藏壁画和部分原址壁画中,为了加固、保护壁画颜料层,在20世纪70~90年代,曾经大量使用加固剂和封护剂对壁画颜料层进行保护修复。受当时修复材料和施工工艺的局限,经过仅40余年的变化,一些早期的保护修复有机材料老化,导致许多壁画出现了新问题,主要表现为眩光、变色、龟裂、起翘等病害,严重影响壁画的长期保存和展陈。文章列举了国内外早期修复材料因老化失效而损害壁画的几桩案例,讨论了现代有机材料的老化对壁画保存的不利影响,并对修复材料的"失效"概念进行了界定和阐述。可以认为,修复材料老化导致壁画外观的变化及保护材料未失效但造成壁画性质改变引发潜在病害的两种情况中任意一种,均可视为修复材料"失效",为了长久保护壁画必须予以清除。最后探讨了清除失效修复材料时使用凝胶清洗和微乳液清洗等方法的有效性和前瞻性。     

南唐二陵壁画历史保护修复材料的分析

为了确定南唐二陵壁画已有保护修复材料的种类,使用多光谱摄影技术分别对钦陵和顺陵壁画保护修复材料的分布区域进行探查,在紫外荧光图像中确定了保护修复材料的位置,通过红外光谱和热裂解-气质联用技术对材料进行了成分分析。结果表明二陵壁画所使用的保护修复材料主要为苯乙烯-甲基丙烯酸甲酯共聚物和聚醋酸乙烯酯,还发现少量多糖类物质,为调和地仗石灰层所使用的糯米汁。该研究表明通过多光谱摄影技术提供线索,使用红外光谱、热裂解-气质联用确定成分是一种可靠的墓葬壁画保护修复材料分析方法体系,为墓葬壁画保护修复材料的鉴别提供借鉴,也为保护修复材料在墓葬壁画中的应用效果评价和劣化机理研究提供参考。     

文物保护用有机高分子材料及要求

物保护是采用自然科学的手段,在尊重物人因素的前提下,恢复物的完整性,并尽量延长物寿命的科学技术,对物进行的修复和保护,必然要采用许多的技术手段和物质材料。有机高分子材料是物保护中使用的一类重要的材料,在物保护中被用做物的加固材料、粘接材料、表面封护材料等。在物保护中使用的高分子材料包括：1．天然有机高分子材料(多糖、蛋白质、蜡等);2．水溶性合成树脂;3．溶剂型合成树脂;4．反应型高分子材料;5．高分子树脂乳液等。对保护材料的性能要求,包括制备、运输、储存、应用效果及安全方面,尤其强调材料的耐久性。另外对用于不同用途的高分子材料,有不同的要求,如表面涂层材料要求不改变物的外观,加固材料要求有好的渗透能力等。     

计算机辅助设计（CAD）在文物修复中的运用

通过计算机辅助设计(CAD)在文物修复这门传统工艺中的运用,进一步提高了在文物修复过程中预想修复效果和制定最佳修复方案的精确性。并借助计算机辅助设计在二维平面、三维立体效果方面的特长,模拟文物破损处复原、去除和保留不同颜色物质、创建和复制器物残缺部分及预览器物安装情况等效果。这样不仅为文物修复提供有利帮助,还使这门传统工艺与当今先进计算机技术得到有机结合。修复实践表明,对那些变形较大,又不想进行破坏性修复的文物来说,三维模拟修复就是唯一的修复方法。     

潼南大佛维修工程中传统材料及工艺应用

在2012年实施的潼南大佛本体维修保护装金工程中,既注重传统材料与现代材料的合理运用,又注重传统工艺和现代科技的有机结合,特别是在大佛泥塑与髹漆和贴金技术等方面,按照"原材料、原工艺"的要求,尽最大可能地挖掘和使用传统材料及传统工艺,保存文物的真实性和完整性,取得了令文物界专家十分满意的修复效果,被评为该年度"全国十大文物保护工程"。     

利用FT-IR、Py-GC/MS和THM-Py-GC/MS微损分析技术探索油画文物复杂的有机基质组成

近现代油画有机基质组分复杂、难辨,其分析鉴定是当今文物保护科技研究的难点之一。利用微损分析技术研究油画文物复杂的基质结构、材料和技法,可以阐明油画特定层的性质和状况,对于专业保护人员制定修复决策至关重要——这对选择正确修复技术非常有用,关系到修复后油画的安全状态,因此已成为许多研究者关注的焦点。本研究利用傅里叶变换红外光谱(FT-IR)、热裂解气相色谱-质谱(Py-GC/MS)和热辅助水解甲基化-裂解气相色谱-质谱(THM-Py-GC/MS)等微损分析技术对一幅中国国家博物馆藏油画《德涅泊尔河的秋天》进行科技分析。研究发现,综合运用这些微损分析技术可以有效识别油画用的胶结介质和其中添加剂的种类,最大限度、准确、完整地提取样品中所蕴含的信息。结果表明,该油画的有机胶结材料为聚乙烯醋酸酯类材料和亚麻籽油,同时聚乙烯醋酸酯类材料中使用了邻苯二甲酸二丁酯作为增塑剂。裂解产物中不含光油树脂类成分,说明画作下部的光亮层并非作者有意上的光油层。此外,油画部分区域还添加了蜂蜡作为改性材料,起到增加颜料稠度、可塑性和减弱光泽的作用。     

江苏东海县博物馆藏青铜器的修复保护

本文介绍了江苏省东海县博物馆藏青铜器的保存状况,并论述了其修复保护方法,包括青铜器锈蚀的处理、破损青铜器的修复以及修复后的保护处理等。在器物修复过程中,使用了一些新的修复材料和方法,提高了修复效率,极大地缩短了修复时间。     

彩绘泥塑文物修复材料的筛选应用——以阿斯塔那古墓群出土彩绘泥塑为例

新疆吐鲁番阿斯塔那古墓群出土的彩绘泥塑文物在1970年代曾经过修复,目前文物出现了粘接部位松动、补缺部位脱落以及全色做旧的颜色发生了变化等情况,究其原因是当时所使用的修复材料出现了问题,如黏合剂老化造成粘接处的松动和脱落,颜料的质量问题使后期的色彩发生了变化,等等。鉴于上述材料已经无法继续对文物实施有效的保护,需要运用科学的手段重新筛选新材料。在选择新材料时,首先对其成分和性能及安全可靠性作了充分了解,以确保新材料在使用中和使用后对于所修复的文物无安全隐患并能够起到真正的保护作用;其次是主要修复材料的质地与文物尽量保持一致。通过仪器检测修复所需的泥土成分和性能,反复实验渗透加固剂的速度、强度、深度、色泽,粘接剂的力度强弱,填补缝隙用料的可塑性以及颜料等,最终选择新型材料和传统材料相结合,作为修复彩绘泥塑文物的基本材料。     

江苏省东海县博物馆藏青铜器的修复保护

为对江苏省东海县博物馆馆藏青铜器进行修复保护,在研究其现状的基础上进行了修复方案的制定和修复保护处理。由于经费、人员及时间的极大限制,除使用常规修复保护方法外,修复保护过程中也尝试使用一些新的材料和方法,以便提高修复的效率并达到较好的展览效果。在修复保护工作完成之后的4年时间,器物保存于东海县博物馆,通过对器物进行跟踪观察,未发现器物出现进一步的劣化,修复保护的效果良好,能够满足现代修复理念对于修复的要求。     

石质文物表面防护中的问题和新材料

野外的大型石质物暴露在自然界的风化环境中,近代环境污染和酸雨使侵蚀更加严重,已有许多防护材料用于石质物的防护,本分析了目前防护材料,特别是憎水性有机高分子防护材料在使用中存在的问题,并初步探索了使用新的生物无机防护材料的可能性。     

典型环氧类粘结材料老化过程的探索性研究

环氧树脂类粘结材料目前已成为文物保护工作中常用的粘结材料。但是,在一些应用案例中经常发现环氧树脂类粘结材料有变色、脆化、剥落等老化现象。为了了解环氧类粘结材料的老化规律,摸清材料成分、配方和环境因素的影响,以通用双酚A型环氧树脂为主剂与各种典型固化剂、稀释剂、偶联剂等配制成黏结材料,模拟自然界极端环境条件,通过反复的破坏循环实验,探讨典型环氧类粘结材料的老化过程和机理。     

利用荧光偏光技术对古木进行腐朽等级判定及加固程度的辨析

古代木材的发掘和保护已成为当今考古学研究的又一重大研究领域。本研究基于海门口遗址的实例,利用荧光、偏光技术对木材解剖学的分析,从而得到古木腐朽等级的划分及加固方法的可行性直观分析。结果表明:古代针叶材的腐朽初步分为4个等级;酚醛树脂加固古木较之天然树脂有更为理想的支撑细胞壁骨架的加固效果。     

CHEMICAL CHARACTERIZATION OF ANCIENT MESOAMERICAN ‘COPAL’ RESINS: PRELIMINARY RESULTS*

So‐called ‘copal’ resins from nine Aztec/Mixtec turquoise mosaics have been subject to analysis by gas chromatography – mass spectrometry to examine their higher terpenoid composition with a view to botanical identification. Botanical specimens and modern commercial ‘copal’ resins were analysed for reference. A range of botanical sources for the resins was identified, including pine, Protium and possibly Bursera. The data reinforce the ambiguity in the use of the term ‘copal’ and demonstrate the need for further work on characterization of ancient Bursera resins.     

COMPOSITIONAL VARIATIONS IN AGED AND HEATED PISTACIA RESIN FOUND IN LATE BRONZE AGE CANAANITE AMPHORAE AND BOWLS FROM AMARNA,EGYPT*

This study examines resinous deposits from the interior surfaces of sherds of imported Canaanite amphorae and locally produced bowls from the 18th Dynasty site of Tell el‐Amarna, Egypt. Archaeological evidence indicates that the Canaanite amphorae were used for resin transport, whilst the bowls are associated with burning resin as incense. A number of characteristic triterpenoids identify all the resinous deposits from both vessel types as Pistacia spp. No other resins were observed and there was no evidence of mixing with oils or fats. The composition of the archaeological resins is more complex than that of modern pistacia resin, due to degradation and generation of new components. Experimental heating alters the relative abundance of the triterpenoid composition of modern pistacia resin. One component, the triterpenoid 28‐norolean‐17‐en‐3‐one, is produced by such heating; however, an increase in its relative abundance in ancient samples is not matched by the archaeological evidence for heating. It is therefore not possible to use this component reliably to identify heated resin. However, additional unidentified components with a mass spectral base peak at m/z 453 have been associated with seven (out of 10) bowls and are not observed in resins associated with Canaanite amphorae. It is proposed that these components are more reliable molecular indicators of heating.     

BULK STABLE LIGHT ISOTOPIC RATIOS IN RECENT AND ARCHAEOLOGICAL RESINS: TOWARDS DETECTING THE TRANSPORT OF RESINS IN ANTIQUITY?*

We have applied and refined methods for the determination of bulk hydrogen, carbon and oxygen isotope ratios in modern and archaeological resins. The modern resins have a wide range of isotopic values and vary within the same tree, between individual trees, with species and location. For all isotopes measured, there is a general trend of increasing depletion of the heavier isotope with increasing altitude. There is also a linear trend between depletion of δD and δ¹³C values with increasing latitude; this trend is less clear for oxygen, but is related to the meteoric water line. Two case studies using archaeological resins known or suspected to have been transported in antiquity have been investigated to determine whether isotopic signatures can assist in pinpointing the geographical origin of the resin: Pistacia sp. resin from Canaanite amphorae imported into Egypt from known geographical locations in the eastern Mediterranean during the Late Bronze Age, and Roman amphorae sherds lined with Pinus sp. resin from sites ranging from Britain to the eastern Mediterranean. These results show separate groupings between the two resin types (pine/pistacia) and between the modern/archaeological resins. Some archaeological samples are distinct from the others and the modern resins show differences between geographical areas. However, there are no clear patterns relating the different Canaanite fabrics or the suggested manufacturing site of the Roman amphorae.     

Stable carbon isotope analysis of subfossil wood from Austrian Alps

The presented studies were carried out in order to check the usefulness of subfossil wood for stable isotope analysis. The aim of research was also to define the optimal method of subfossil samples preparation. Subfossil samples used during the presented studies are a part of the multicentury dendrochronological scale. This chronology originates in an area situated around a small mountain lake — Schwarzersee, in Austria. The obtained results of stable carbon isotope measurements confirmed that the method of α-cellulose extraction by the application of acidic sodium chlorite and sodium hydroxide solutions removes resins and other mobile compounds from wood. Therefore, in the case of the analysed samples, the additional chemical process of extractives removing was found to be unnecessary. Studied wood samples contained an adequate proportion of α-cellulose similar to the values characteristic for the contemporary trees. This proved an adequate wood preservation which is essential for the conduction of isotopic research.     

A new method to remove copper corrosion stains from stone surfaces

This paper reports on a methodological study carried out in order to propose a cleaning procedure to remove stains produced by bronze corrosion products on surface of limestone (namely travertine); the procedure is effective and more environmentally friendly than the methods commonly used today. Several copper complexing or chelating agents were considered, including three amino acids and compared with some ion exchange resins. After a first laboratory phase on pure copper products and on artificially stained quarry samples, the optimized procedure was tested on the pedestal of a bronze statue in the Sapienza campus, in Rome. Colorimetry and ICP/OES were used to evaluate the efficiency of the cleaning procedure.     

CHARACTERIZATION OF NATURAL PRODUCTS ON NATIVE AMERICAN ARCHAEOLOGICAL AND ETHNOGRAPHIC MATERIALS FROM THE GREAT BASIN REGION,U.S.A.: A PRELIMINARY STUDY

Although documentary evidence provided by ethnographers makes reference to the source of adhesives, sealants, dyestuffs and medicines used by the communities of the Great Basin, much of it is sporadic and unspecified. However, observations of amorphous deposits surviving on stone tools, ceramics, basketry and wooden artefacts have prompted an investigation of their identity, procurement and use. The aim initially is to study samples from a number of archaeological and ethnographic contexts from the region. Comparative material includes higher plant and insect resins. The study provides a unique opportunity to document use patterns in plant and animal resources in the Great Basin region.     

RECONSTRUCTING ANCIENT YEMENI COMMERCIAL ROUTES DURING THE MIDDLE AGES USING STRUCTURAL CHARACTERIZATION OF TERPENOID RESINS*

Following the discovery of items that look like resins at the medieval site of Sharma (Hadramawt coast, Yemen, c. 11th century ad ), chemical investigations were carried out in order to determine their nature and geographic origin. By combining visual observation, infrared spectroscopy, direct inlet electron ionization – mass spectrometry (DI EI–MS) and pyrolysis gas chromatography – mass spectrometry (Py GC–MS) or gas chromatography – mass spectrometry (GC–MS) analyses, it was demonstrated that 84% of the samples were harvested from Hymenaea trees growing in Madagascar and East Africa. Contrary to what was thought previously, frankincense, identified with certainty in only two samples, was thus not the main resin exploited at Sharma. These results are of prime importance for reconsidering the trading routes of resins passing through Sharma, a site that was obviously strongly connected with Africa during the Middle Ages.     

ANALYSIS OF EUROPEAN AMBER BY CARBON-13 NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY

Amber, a class of fossil resins, comprises largely terpenoid components. The structure of the major, insoluble portion has not been defined previously. We report the analysis of European amber by carbon-13 nuclear magnetic resonance spectroscopy directly on solid samples. Two major types are defined, depending on the appearance of the alkene resonances. Baltic amber (succinite), along with other northern ambers such as gedanite, has a pronounced resonance from an exomethylene group. The southerly ambers (rumanite, schraufite, walchowite, delatynite and true simetites) lack the exomethylene resonances. The succinite group gives spectra consistent with a labdane-type precursor and the rumanite-like ambers give spectra consistent with an abietane-type precursor. These results are best explained by at least two different palaeobotanical sources of the fossil resins.