Bøger af Howell G. M. Edwards

This book addresses the application of Raman spectroscopic techniques to a range of diverse problems which arise in the study, conservation and restoration of artefacts and sites closely related to our cultural heritage as well as in authentication. These themes are naturally wider than what at first might be considered as artworks and archaeological artefacts and the topics include pigments, paintings, ceramics, glass, sculpture and patination / corrosion, textiles, industrial archaeology, the degradation and preservation of biomaterials, mummies and human skeletal remains. An interesting feature is the inclusion of modern case studies which describe specific problems and approaches to the Raman spectral analysis of items important to our cultural heritage. The text is prefaced with an introduction to the important parameters used in nondestructive Raman measurements and also highlights some future applications based upon novel miniaturised instrumentation for in-field studies and potential screening work which will identify specimens which would repay further studies in the laboratory. An attempt is made to give a snapshot of the state-of-the-art evolution since the beginning of the technique (1970s) and to point out potential further development. The book is co-edited by three international experts with many years' experience in the application of Raman spectroscopy to artworks, archaeological artefacts and in the investigation of materials and sites for cultural heritage preservation and each editor has undertaken to write individual chapters and different topics personally. The adopted approach is designed to convey the sort of information which has become available from the adoption of analytical Raman spectroscopy to different problems in the field of cultural heritage preservation through the spectral interrogation of artefacts and how the interpretation of the spectral data can assist museum curators, archaeologists and cultural heritage historians in the preservation and conservation of ancient materials and sites : a particular advantage in this respect is the ability of Raman spectroscopy to determine -generally in a strictly noninvasive procedure - at the laboratory or on-site with mobile instruments, the presence of both organic and inorganic components in a particular specimen together nondestructively without any chemical and mechanical pretreatment being undertaken, which is an essential requirement for rare and valuable samples . An important aside from this work is the means of spectral identification of ongoing biodeterioration and biological colonisation in specimens in storage and the effects of environmental deterioration such as humidity and temperature upon their integrity.

Armorial porcelains comprised the output of most European ceramics factories in the 18th and 19th Centuries in response to the large quantity of armorial porcelain services that were being imported from China bearing the coats of arms and crests of aristocratic families. Whereas these armorial services have been identified and covered for most porcelain manufactories the information relevant to their production by the two relatively short-lived Nantgarw and Swansea China Works has not been addressed as a theme until now. As an integral  component  of  the holistic forensic appraisal of porcelain, a functional and decorative artwork manifestly part of our cultural heritage and its ongoing preservation ,  the recording and identification of such artefacts is material for the future establishment of a database of factory production . The Nantgarw and Swansea factories only operated for a limited period in the second decade of the 19th Century and their porcelains were much appreciated  for their high quality and desirability by Georgian households. Today, examples are to be found in many museums and  ceramics collections and continue to excite the interest of specialists and the general public . This text provides the first comprehensive assessment of armorial porcelains from these two factories and the methodology and procedure for the identification of unknown armorial bearings and crests is illustrated; individual bearings are discussed  in detail and existing incorrect assignments in the literature are re-appraised. The difficulties in attribution of armorial heraldic achievements that are only minimally depicted are considered and directions for further studies using historical documentation are invoked. This book therefore fills a currently existing gap in the ceramics literature of the 19th Century. 

This book covers the discovery and the results of the analytical study of the composition of the Farnley Hall service, involving both the embossed moulding and the decorative compositions. The discovery of this missing porcelain service, which was manufactured 200 years ago, is a modern detective story in the preservation of cultural heritage, whilst its physical analysis has identified some new data that need to be incorporated into correcting and expanding the literature that is used for the differentiation of porcelains by ceramic historians and museum conservators. The importance of the Farnley Hall service discovery is that it provides the only example of such a Nantgarw Porcelain service that still resides in its original place of usage from 200 years ago: it is therefore a unique example and is a very important part of our national cultural heritage. It provides an illustration of the data that can be accessed from the application of inductive reasoning to elicit novel information about a manufactory whose work books no longer exist and its comparison with contemporary manufactories in the late eighteenth and early nineteenth centuries. The concepts can be appreciated by experts and also by non-technical readers. This is the first time that such a detailed research approach has been adopted for any comparative ceramic project. The book is therefore relevant for a specialist and non-specialist readership, including museum ceramics curators and collectors of the genre.

The material for this book arose from the author¿s research into porcelains over many years, as a collector in appreciation of their artistic beauty , as an analytical chemist in the scientific interrogation of their body paste, enamel pigments and glaze compositions, and as a ceramic historian in the assessment of their manufactory foundations and their correlation with available documentation relating to their recipes and formulations. A discussion of the role of analysis in the framework of a holistic assessment of artworks and specifically the composition of porcelain, namely hard paste, soft paste, phosphatic, bone china and magnesian, is followed by its growth from its beginnings in China to its importation into Europe in the 16th Century. A survey of European porcelain manufactories in the 17th and 18th Centuries is followed by a description of the raw materials, minerals and recipes for porcelain manufacture and details of the chemistry of the high temperature firing processes involved therein. The historical backgrounds to several important European factories are considered, highlighting the imperfections in the written record that have been perpetuated through the ages. The analytical chemical information derived from the interrogation of specimens, from fragments, shards or perfect finished items, is reviewed and operational protocols established for the identification of a factory output from the data presented. Several case studies are examined in detail across several porcelain manufactories to indicate the role adopted by modern analytical science, with information provided at the quantitative elemental oxide and qualitative molecular spectroscopic levels, where applicable. The attribution of a specimen to a particular factory is either supported thereby or in some cases a potential reassessment of an earlier attribution is indicated. Overall, the information provided by analytical chemical data is seen to be extremely useful for porcelain identification and for its potential attribution in the context of a holistic forensic evaluation of hitherto unknown porcelain exemplars of questionable factory origins.