Papers by Kristalia Melessanaki
Zenodo (CERN European Organization for Nuclear Research), Jun 12, 2019
Noninvasive photoacoustic detection of hidden underdrawings in paintings using air-coupled transd... more Noninvasive photoacoustic detection of hidden underdrawings in paintings using air-coupled transducers, Ultrasonics (2019), doi:
... Phys. J. D: Atom. Mol. Opt. Phys. 13, 373-377 (2001). 6. Acknowledgments The authors wish to ... more ... Phys. J. D: Atom. Mol. Opt. Phys. 13, 373-377 (2001). 6. Acknowledgments The authors wish to thank the Institute for Aegean Prehistory (INSTAP) and the Foundation for Research and Technology-Hellas (FORTH-IESL) for funding and collaboration on this project. ...
Opto-Electronic Advances, 2020
In the context of this work, a prototype hybrid photoacoustic (PA) and optical system for the on-... more In the context of this work, a prototype hybrid photoacoustic (PA) and optical system for the on-line monitoring of laser cleaning procedures is presented. The developed apparatus has enabled the detection of MHz frequency range acoustic waves generated during the laser ablation process. The intrinsically generated PA signals combined with high resolution optical images provide the opportunity to follow the cleaning process accurately and in real time. Technical mock-ups have been used to demonstrate the potential of this novel technique with emphasis given to applications that refer to the restoration of Cultural Heritage (CH) surfaces. Towards this purpose, the real time monitoring of the laser assisted removal of unwanted encrustation from stonework has been achieved using IR and UV wavelengths. This novel approach has allowed for the precise determination of the critical number of laser pulses required for the elimination of the encrustation layer, while highlighting the dominant ablation mechanisms according to the irradiation wavelength. The promising results obtained using the prototype hybrid PA and optical system can open up new perspectives in the monitoring of laser cleaning interventions, promoting an improved restoration outcome.
Construction and Building Materials, 2019
h i g h l i g h t s Laser cleaning of a gypsum black crust on a fine-grained granite was evaluate... more h i g h l i g h t s Laser cleaning of a gypsum black crust on a fine-grained granite was evaluated. 1064 nm and 355 nm of a Nd:YAG laser were applied simultaneously to clean a crust on granite. Different F IR/ F UV ratios (1/1, 1/3 and 3/1) were applied (fluences from 0.1 up to 0.9 JÁcm À2). Gypsum black crust extraction and damages induced on the granite forming minerals were evaluated. The best results were achieved with the simultaneous application of 0.3 JÁcm À2 at 1064 nm and 355 nm on a pre-wetted surfaces.
Journal of Applied Physics, 2018
This study introduces a novel method for the thickness estimation of thin paint layers in works o... more This study introduces a novel method for the thickness estimation of thin paint layers in works of art, based on photoacoustic signal attenuation analysis (PAcSAA). Ad hoc designed samples with acrylic paint layers (Primary Red Magenta, Cadmium Yellow, Ultramarine Blue) of various thicknesses on glass substrates were realized for the specific application. After characterization by Optical Coherence Tomography imaging, samples were irradiated at the back side using low energy nanosecond laser pulses of 532 nm wavelength. Photoacoustic waves undergo a frequency-dependent exponential attenuation through the paint layer, before being detected by a broadband ultrasonic transducer. Frequency analysis of the recorded time-domain signals allows for the estimation of the average transmitted frequency function, which shows an exponential decay with the layer thickness. Ultrasonic attenuation models were obtained for each pigment and used to fit the data acquired on an inhomogeneous painted mo...
Insight - Non-Destructive Testing and Condition Monitoring, 2018
Scientific Reports, 2017
A novel, non-invasive, imaging methodology, based on the photoacoustic effect, is introduced in t... more A novel, non-invasive, imaging methodology, based on the photoacoustic effect, is introduced in the context of artwork diagnostics with emphasis on the uncovering of hidden features such as underdrawings or original sketch lines in paintings. Photoacoustic microscopy, a rapidly growing imaging method widely employed in biomedical research, exploits the ultrasonic acoustic waves, generated by light from a pulsed or intensity modulated source interacting with a medium, to map the spatial distribution of absorbing components. Having over three orders of magnitude higher transmission through strongly scattering media, compared to light in the visible and near infrared, the photoacoustic signal offers substantially improved detection sensitivity and achieves excellent optical absorption contrast at high spatial resolution. Photoacoustic images, collected from miniature oil paintings on canvas, illuminated with a nanosecond pulsed Nd:YAG laser at 1064 nm on their reverse side, reveal clea...
Microscopy and Microanalysis, 2016
In this work, we report that polarization second harmonic generation (PSHG) microscopy, commonly ... more In this work, we report that polarization second harmonic generation (PSHG) microscopy, commonly used in biomedical imaging, can quantitatively discriminate naturally aged from fresh starch-based glues used for conservation or restoration of paintings, works of art on paper, and books. Several samples of fresh and aged (7 years) flour and starch pastes were investigated by use of PSHG. In these types of adhesives, widely used in cultural heritage conservation, second harmonic generation (SHG) contrast originates primarily from the starch granules. It was found that in aged glues, the starch SHG effective orientation (SHG angle, θ) shifts to significantly higher values in comparison to the fresh granules. This shift is attributed to the different degree of granule hydration between fresh and aged adhesives. Thus noninvasive high-resolution nonlinear scattering can be employed to detect and quantify the degree of deterioration of restoration adhesives and to provide guidance toward fu...
Heritage Science, 2016
A versatile analytical methodology is presented, that combines the application of two mobile lase... more A versatile analytical methodology is presented, that combines the application of two mobile laser-based analytical techniques, Raman microscopy and laser-induced breakdown spectroscopy (LIBS), for the analysis of materials in historical and archaeological objects and monuments. In the present study, the proposed methodology was employed in the context of analytical campaigns aiming to investigate paint materials used on the island of Crete during the Venetian and Ottoman periods, thirteenth to nineteenth century CE. The first series of campaigns were conducted at the Historical Museum of Crete, Heraklion, Greece, and provided for the first time compositional data concerning the pigment palette used for painting Ottoman sculpture in Crete. In the second series, campaigns were performed outdoors for studying pigments in the sculptured door frames of two small medieval churches situated at rural locations in the greater Heraklion area. Raman and LIBS analyses gather complementary compositional data, molecular and elemental respectively, which, taken jointly, enable, in most cases, identification of pigments and accessory materials in paint layers, providing also stratigraphic information. With both instruments, measurements are performed directly on the surface of the objects or monuments, with no need for any sampling or sample preparation and thus analytical studies can be conducted rapidly and routinely in the context of a museum setting, a conservation laboratory or even outdoors. A standardized procedure that facilitates data collection and interpretation, interdisciplinary cooperation and presentation of results is adopted that optimizes the overall efficiency of the analytical campaigns.
Springer Proceedings in Physics
... The painting in question is a minimalist work of art created by the New York based painter Ad... more ... The painting in question is a minimalist work of art created by the New York based painter Ad Reinhardt. The painting was deemed unexhibitable and is now in the study collection of the Solomon R Guggenheim Museum. This ...
CLEO/Europe. 2005 Conference on Lasers and Electro-Optics Europe, 2005.
Microscopy and Microanalysis, 2014
The present work investigates the applicability of nonlinear imaging microscopy for the precise a... more The present work investigates the applicability of nonlinear imaging microscopy for the precise assessment of degradation of the outer protective layers of painted artworks as a function of depth due to aging. Two fresh and artificially aged triterpenoid varnishes, dammar and mastic, were tested. Nonlinear imaging techniques have been employed as a new diagnostic tool for determination of the exact thickness of the affected region due to artificial aging of the natural varnishes. The measured thicknesses differ from the calculated mean penetration depths of the samples. These nondestructive, high resolution modalities are valuable analytical tools for aging studies and they have the potential to provide unique in-depth information. Single photon laser induced fluorescence measurements and Raman spectroscopy were used for the integrated investigation and analysis of aging effects in varnishes.
Journal of Archaeological Science, 2006
... spectroscopy (LIBS) [2], [3], [26] and [52] to determine the elemental content of painted pla... more ... spectroscopy (LIBS) [2], [3], [26] and [52] to determine the elemental content of painted plaster from Eastern Mediterranean Bronze Age ... in several laboratories has demonstrated LIBS to be a valuable method for addressing problems related to art conservation and archaeology ...
NDT & E International, 2014
Custom-made fresco samples covered in artificial crust were laser cleaned, and the consequent mec... more Custom-made fresco samples covered in artificial crust were laser cleaned, and the consequent mechanical effects were tested with digital holographic speckle pattern interferometry (DHSPI). DHSPI proved capable of detecting the structural alterations in the fresco. It was shown that the laser cleaning process caused no structural damage to the intact samples and has not worsen the damages in case such were originally present. Quantitative evaluation of the fringe patterns revealed that the potential risk of laser cleaning is negligible on the mechanical structure of the frescos. Consolidation with Remmers KSE 300 has improved the laser cleaning efficiency in the UV.
Springer Proceedings in Physics
... corroded grey material covering the bead was actually the remainder of a silver coating. ... ... more ... corroded grey material covering the bead was actually the remainder of a silver coating. ... Quantitative analysis by LIBS is also possible using proper reference samples or alternative calibration ... Copper and bronze were common materials in the Bronze Age for making all types ...
INSTAP Academic Press (Institute for Aegean Prehistory) eBooks, Jul 1, 2003
Universal Journal of Physics and Application
The photo-induced effects generated upon laser cleaning result to the removal of unwanted materia... more The photo-induced effects generated upon laser cleaning result to the removal of unwanted material, still transient deformation and damage on the surface and the structure of the materials can be also occurred. It is herein presented a laser-based workstation to monitor deformation and to evaluate any damage potentially induced by laser cleaning processes in a non-destructive and on-line methodology. An all-optics laser geometry, which allows the alignment of the ablation beam and the monitoring system, is enabled. On-line surface monitoring of photomechanical effects is performed through the acquisition of surface condition and its relevant displacement associated to the synchronously performed laser cleaning procedure. Surface condition is traced by interference generated patterns expressed in spatial coordinates and their alterations throughout the cleaning process. Transient deformation, damage, successful or successful intervention is deduced upon comparison of the last to the initial-reference position of the surface points. The all-optics laser-workstation aims to respond to the increasing demand of controlled interventions satisfying safety regulations and preventive measures to be taken on time. As a proof of application principle infrared (IR) laser-cleaning in the removal of varnish from wooden objects monitored with the synchronized coherent interferometry system, is presented.
Communications in Computer and Information Science, 2019
Cultural Heritage (CH) outdoor monuments are susceptible to severe and extreme weather phenomena ... more Cultural Heritage (CH) outdoor monuments are susceptible to severe and extreme weather phenomena as a result of the climatic change. The prompt detection and analysis, as well as the continuous monitoring of weathering formations and deterioration products is thus crucial for their preservation and longevity.
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Papers by Kristalia Melessanaki