Mixed X-Ray Image Separation for Artworks with Concealed Designs

In this paper, we focus on X-ray images of paintings with concealed sub-surface designs (e.g., deriving from reuse of the painting support or revision of a composition by the artist), which include contributions from both the surface painting and the concealed features. In particular, we propose a self-supervised deep learning-based image separation approach that can be applied to the X-ray images from such paintings to separate them into two hypothetical X-ray images. One of these reconstructed images is related to the X-ray image of the concealed painting, while the second one contains only information related to the X-ray of the visible painting. The proposed separation network consists of two components: the analysis and the synthesis sub-networks. The analysis sub-network is based on learned coupled iterative shrinkage thresholding algorithms (LCISTA) designed using algorithm unrolling techniques, and the synthesis sub-network consists of several linear mappings. The learning algorithm operates in a totally self-supervised fashion without requiring a sample set that contains both the mixed X-ray images and the separated ones. The proposed method is demonstrated on a real painting with concealed content, Do\~na Isabel de Porcel by Francisco de Goya, to show its effectiveness

Assessment of plastics in the National Trust: a case study at Mr Straw's House

The National Trust is a charity that cares for over 300 publically accessible historic buildings and their contents across England, Wales and Northern Ireland. There have been few previous studies on preservation of plastics within National Trust collections, which form a significant part of the more modern collections of objects. This paper describes the design of an assessment system which was successfully trialled at Mr Straws House, a National Trust property in Worksop, UK. This system can now be used for future plastic surveys at other National Trust properties. In addition, the survey gave valuable information about the state of the collection, demonstrating that the plastics that are deteriorating are those that are known to be vulnerable, namely cellulose nitrate/acetate, PVC and rubber. Verifying this knowledge of the most vulnerable plastics enables us to recommend to properties across National Trust that these types should be seen as a priority for correct storage and in-depth recording

Optical techniques applied to measurements in art

Optical diagnostic techniques are particularly attractive for the non-destructive detection of incipient damage and the evaluation of the state of surface decay. Non-contact, high precision measurements of the shape and deformation of an artifact can be performed using laser methods based on holographic and speckle interferometry. [Continues.

Giovanni Bellini: experience and experiment in Venetian painting, c. 1460-1516

Giovanni Bellini (b. 1435/40-d. 1516) has long been considered a dominant figure in the Venetian painting of the Early-High Renaissance, his main reputation being a colourist. The distinctive optical and technical characteristics of his work have drawn substantial scholarly attention in the present century, but the studies in this subject have not been developed as a coherent theory with regard to changes in painting technique in the fiftenth-century Italy. The purpose of this dissertation, therefore, is to investigate Bellini's choice and application of painting materials, attempting to establish links between the technical qualities and the formal values of his work. In the process of establishing Bellini's position with regard to the use of paint media and support, this thesis also provides a substantial overview of the use of canvas and of oil pain in the later fifteenth century. The study is encouraged by recent discoveries about Bellini's technique that have emerged from conservation of his paintings. As well as addressing published conservation results, the thesis includes new observations on four canvases attributed to Bellini's father Jacopo, and two Madonnas from Bellini's workshop scientifically examined at UCL Painting Analysis. In order to investigate Bellini's colour and handling of paint within a broader socio-economic milieu, this study deals with the commercial documents such as tariffs, government records, and merchant account books, indicating that Venice was the centre of the international colour trade and that Venetians were widely engaged with this trade. The resulting advantages of Venetian painters who were active at this commercial heart, and the question of how deeply the pragmatic experience of colours that Venetian merchants obtained from the trade penetrated their aesthetic taste will be discussed. Using both scientific and documentary analyses in combination with visual analysis which integrates these findings, this study examines Bellini's translation of the skills of tempera to oil pain and the stylistic changes that occurred with the extensive use of oil medium. It looks at how Bellini developed canvas as a support for mural painting and the technique he employed on such an unconventional support. It will also study the methods in which he established the predominance of colour as an element of composition at the early sixteenth century. In conclusion, it will argue that Bellini's increasing choice of canvas and corresponding use of oil on it changed the general concept of picture-making and became a new format of painting that was to exert a crucial influence on Cinquecento Venetian painting

Aiding the conservation of two wooden Buddhist sculptures with 3D imaging and spectroscopic techniques

The conservation of Buddhist sculptures that were transferred to Europe at some point during their lifetime raises numerous questions: while these objects historically served a religious, devotional purpose, many of them currently belong to museums or private collections, where they are detached from their original context and often adapted to western taste. A scientific study was carried out to address questions from Museo d'Arte Orientale of Turin curators in terms of whether these artifacts might be forgeries or replicas, and how they may have transformed over time. Several analytical techniques were used for materials identification and to study the production technique, ultimately aiming to discriminate the original materials from those added within later interventions

X-ray fluorescence applied to yellow pigments based on lead, tin and antimony: comparison of laboratory and portable instrumentation

X-ray fluorescence is a diagnostic approach particularly suited to be utilized in cultural heritage sector since it falls in the non-destructive and non-invasive analytical tools. However there are big differences between portable and laboratory instrumentation that make difficult to perform a comparison in terms of quality and reliability of the results. The present study is specifically addressed to investigate these differences in respect of the same analytical sample-set. To reach this goal a comparison was thus carried out between portable and bench top devices X-ray fluorescence devices and techniques were used on different type of yellow pigments based on lead, tin and antimony obtained in laboratory, reproducing the instructions described in “old” recipes, that is: i) mortar of lead and tin produced on the basis of the recipe 13 /c V of the “Manuscript of Danzica” and “ Li tre libri dell’arte del Vasaio” by Cipriano Piccolpasso; ii) two types of lead and tin yellow (Pb2SnO4 and PbSnO3) produced starting from the indications of the 272 and 273 recipes of the “Bolognese Manuscript”; iii) lead antimonate (Pb2Sb2O7) obtained by following the instructions of the Piccolpasso’s treatise and those contained on the “Istoria delle pitture in maiolica fatte in Pesaro e ne’ luoghi circonvicini di Giambattista Passeri” and finally iv) lead, tin and antimony yellow (Pb2SnSbO6,5) obtained starting from the information contained in the paper 30 R of “Manuscript of Danzica” [1]. The XRF analysis were performed using a laboratory instrumentation (Bruker M4 Tornado) and a handset analytical device (Assing Surface Monitor). In order to perform a significant statistical comparison among acquired and processed data, all the analyses have been carried out utilizing the same sample, the same acquisition set up and operative conditions. A chemometric approach, based on the utilization of Principal Component Analysis (PCA) and multivariate analytical based tools [2], was utilized in order to verify the spectral differences, and related informative content, among the different produced yellow pigments. The multivariate approach on the results revealed instrumental differences between the two systems and allowed to compare the common characteristics of the set of pigments analyzed

Computer Aided Analysis of Underdrawings in Infrared Reflectograms †

Recent developments in computer vision are providing powerful tools for the evaluation of data gathered by art historians and archaeologists. New camera hardware allows new insights into cultural heritage, especially if infrared cameras are concerned, since they allow the of study structures that are visually hidden. In this paper preliminary results of developing a system for automatic analysis of infrared reflectograms are presented. We concentrate on an algorithm for the automatic segmentation of strokes in underdrawings- the basic concept of the artist- in ancient panel paintings and the removal of cracks in infrared images. The purpose of the stroke analysis is the determination of the drawing tool used to draft the painting. This information allows significant support for a systematic stylistic approach in the analysis of paintings. Stroke segmentation in paintings is related to the extraction and recognition of handwriting, therefore similar techniques to segment the strokes from the background incorporating boundary information are used. Results of the algorithms developed are presented for both test panels and real reflectograms. 1

Interdisziplinäre Kooperation bei der Erstellung virtueller geschichtswissenschaftlicher 3D-Rekonstruktionen

Virtuelle 3D-Modelle finden in den historischen Disziplinen in zweierlei Art Verwendung. Zum einen dienen diese zur Erfassung und Digitalisierung existierender historischer Objekte. Daneben dient die Erstellung von virtuellen 3D-Rekonstruktionen der Nachbildung nicht mehr existierender Objekte und Strukturen. Während technische Abläufe beider Ansätze ebenso wie methodische und wissenschaftstheoretische Aspekte in der Fachliteratur häufig und umfassend thematisiert werden, ist eine Frage nach sozialen Aspekten und sozialer Interaktion im Kontext derartiger Vorhaben bisher unbeleuchtet geblieben. Ziel der Arbeit stellt dar, eine Bandbreite und Relevanz von Aspekten der Kooperation als „Zusammenarbeit mit gemeinsamem Ziel, gegenseitiger Abstimmung, planvollem Vorgehen sowie Vorteilen für alle Akteure“ (Hagenhoff, 2004) im Kontext derartiger geschichtswissenschaftlicher 3D-Modellierungsvorhaben mittels sozialwissenschaftlicher Methoden zu beleuchten. Dabei zielt eine Darlegung auf unterschiedliche Skalierungen von Kooperation ab – angefangen bei einer Wissenschaftslandschaft über Kooperationsstrukturen bis hin zu einer Betrachtung von spezifischen Kooperationsphänomenen und -strategien innerhalb von Arbeits- und Erstellungsprozessen