Sotiria Kogou

• PhD
• Academic Fellow at Nottingham Trent University

Historical buildings are prone to deterioration due to moisture and salt activity. Salt weathering affects the appearance of monuments, resulting in mechanical degradation. Many laboratory-based studies have been performed focusing on understanding salt formation in building materials and the resulting damage mechanisms. However, large-scale in sit...

This paper presents a novel multimodal remote sensing setup to analyze the complex stratigraphy of historical wall paintings at distances of order 10 m. The proposed method enables comprehensive investigation of the chemical composition of multilayer paint stratigraphy by combining standoff laser-induced breakdown spectroscopy for elemental profili...

A mobile remote standoff Raman spectroscopy system operational at typical distances of 10 m was developed specifically for research of historical sites and wall paintings recently. Here we present an upgrade to that system informed by a thorough experimental investigation of the relevant laser-induced degradation issues. Reflectance spectroscopy as...

Ancient bronze is subject to complex degradation which can lead, in cases where copper chlorides are present, to a cyclic and self-sustaining degradation process commonly referred to as “bronze disease”. If left untreated, bronze disease can eat away at a bronze object until it is entirely deteriorated. The presence of copper trihydroxychlorides is...

Automatic remote reflectance spectral imaging of large painted areas in high resolution, from distances of tens of meters, has made the imaging of entire architectural interior feasible. However, it has significantly increased the volume of data. Here we present a machine learning based method to automatically detect ‘hidden’ writings and map mater...

Self‐organising map (SOM), an unsupervised machine learning algorithm based on neural networks, is applied to introduce a novel approach for the analysis of XRF spectral imaging data. This method automatically reduced hundreds of thousands of XRF spectra in a spectral image dataset to a handful of distinct clusters that share similar spectra. In th...

This paper investigates the use of Optical Coherence Tomography (OCT) and Short-wave Infrared (SWIR) spectral imaging to study the deterioration of a Limoges enamel panel. Limoges enamels are formed of glass layers applied on a metal substrate and are prone to glass disease. However, the level of deterioration in Limoges enamels is generally diffic...

Portable and mobile Raman spectroscopy systems are increasingly being adopted in in situ non-invasive examination of artworks given their high specificity in material identification. However, these systems typically operate within centimeter range working distances, making the examination of large architectural interiors such as wall paintings in c...

The aim of this research was to use non-invasive scientific analysis to uncover evidence of the planning process and relationship between pigments used in text copying and artwork production in the Oppenheimer Siddur (Oxford Bodleian Library MS Opp. 776), an illuminated 15th-century Hebrew prayer book. In many medieval Hebrew illuminated manuscript...

This paper examines for the first time the potential complementary imaging capabilities of Optical coherence tomography (OCT) and non-linear microscopy (NLM) for multi-modal 3D examination of paintings following the successful application of OCT to the in situ, non-invasive examination of varnish and paint stratigraphy of historic paintings and the...

Since the ‘rediscovery’ of the Selden map of China, an early seventeenth century map of Asia, in the Bodleian Library in Oxford, the importance of the map in our understanding of globalisation in the early seventeenth century has been recognised. One of the unresolved questions is the origin of the map. This paper addresses the question through mat...

A holistic approach using non-invasive multimodal imaging and spectroscopic techniques to study the materials (pigments, drawing materials and paper) and painting techniques of watercolour paintings is presented. The non-invasive imaging and spectroscopic techniques include VIS-NIR reflectance spectroscopy and multispectral imaging, micro-Raman spe...

In this study, the reaction of widely used artist's pigments in raw form to pulsed laser radiation of different wavelengths and pulse duration was investigated. Vermilion, lead chromate and malachite (in the form of pellets) were irradiated using laser pulses of 500fs at 248nm, and pulses of 150ps and 15ns at 1064 and 213nm. Optical microscopy, col...

A new diagnostic approach for assessing the in-depth laser induced modifications upon ultraviolet polymer irradiation is presented. The methodology relies on the observation of morphological alterations in the bulk material (Paraloid B72) by using third harmonic generation. This non destructive methodology allows the detailed and accurate imaging o...

A new portable spectral imaging system is herein presented capable of acquiring images of high resolution (2MPixels) ranging from 380 nm up to 950 nm. The system consists of a digital color CCD camera, 15 interference filters covering all the sensitivity range of the detector and a robust filter changing system. The acquisition software has been de...