Art under a new Light, i.e. how photonics can support the conservation of cultural heritage

Transcription

1 Art under a new Light, i.e. how photonics can support the conservation of cultural heritage Gianluca Valentini Department of Physics, Politecnico di Milano ICT Key Enabling Technologies at the service of European Citizens and Cities Rome 29/30 October 2014

2 UNESCO definition of cultural heritage What is meant by "cultural heritage"? The term cultural heritage encompasses several main categories of heritage: Cultural heritage Tangible cultural heritage: movable cultural heritage (paintings, sculptures, coins, manuscripts) immovable cultural heritage (monuments, archaeological sites, and so on) underwater cultural heritage (shipwrecks, underwater ruins and cities) Intangible cultural heritage: oral traditions, performing arts, rituals Natural heritage: natural sites with cultural aspects such as cultural landscapes, physical, biological or geological formations Heritage in the event of armed conflict 2

3 The scientific approach to conservation Material aging, climate change, atmospheric pollution, anthropic pressure pose serious threats to our cultural heritage Inappropriate conservation and restoration procedures have also contributed to degradation of works of art The modern approach to conservation requires a deep scientific investigation before any treatment IN-SITU DIAGNOSTIC VIS-IR Reflectance UV Fluorescence Vibrational spectroscopy X-Ray fluorescence (XRF) LIBS MONITORING Microclimate monitoring Particulate matter analysis Colour monitoring LAB. DIAGNOSTIC Light microscopy μft-ir and μraman GC-MS Analysis Biodeterioration analysis 3

4 In-situ imaging diagnostic techniques Area Imaging / Analysis Reflectance Visible - NIR Hypespectral UV Fluorescence Broadband Hypespectral NON-invasive Fluorescence Lifetime Imaging Digital holography 4

5 In-situ imaging diagnostic techniques Area Imaging / Analysis Reflectance Visible - NIR Hypespectral UV Fluorescence Broadband Hypespectral NON-invasive Fluorescence Lifetime Imaging Digital holography 5

6 Visible and Infrared Reflectography Netherlandish The Magdalen [NG719] (detail)

7 Scanning multispectral reflectance imaging - High resolution 100 DPI - 13 infrared bands nm - 3 VIS bands (RGB) Courtesy of Raffaella Fontana 7

8 Scanning multispectral reflectance imaging system Courtesy of Raffaella Fontana R G B 0.25 mm (101.6 dpi, 4 pti/mm) 952 nm 1112 nm 1300 nm 1500 nm 1700 nm 1930 nm 2265 nm wavelength 8

9 Scanning multispectral reflectance imaging The hidden window in Caravaggio painting 1300 nm nm R 1112 nm 850 nm G 1300 nm 952 nm B 1930 nm 1200 nm Caravaggio, Cena in Emmaus Milano, Pinacoteca di Brera Courtesy of Raffaella Fontana 9

10 High performance Vis-NIR IFAC-CNR scanner Map of ultramarine blue - Spectral range nm - High resolution images ( ~ 289 ppi) - High resolution spectra 512 VIS NIR Courtesy of Marcello Picollo 10

11 In-situ imaging diagnostic techniques Area Imaging / Analysis Reflectance Visible - NIR Hypespectral UV Fluorescence Broadband Hypespectral NON-invasive Fluorescence Lifetime Imaging Digital holography 11

12 UV-induced fluorescence of works of art A variety of fluorescent material can be found in paintings: binding media natural colorants, lakes, biological contaminants restoration and protective materials. Main features of fluorescence Non-destructive Applicable as an imaging technique Applicable in situ and in remote analysis (LIDAR techniques) Organic binding medium Fluorescent pigments 12

13 UV-Induced Fluorescence Photography White UV light Michelangelo Buonarroti ( ) David - Museo dell Accademia, Florence Presence of organic contaminants adsorbed to the marble surface 13

14 In-situ imaging diagnostic techniques Area Imaging / Analysis Reflectance Visible - NIR Hypespectral UV Fluorescence Broadband Hypespectral NON-invasive Fluorescence Lifetime Imaging LIDAR Fluorescence Imaging 14

15 Fluorescence Lifetime Imaging (FLIM) Intensity Fluorescence temporal decay I( t) = A e -t t A = fluorescence amplitude τ = fluorescence lifetime time (ns) Lifetime map [ns] Amplitude map The lifetime map allows one to distinguish the presence of different fluorescent compounds in the analysed area 15

16 Fluorescence Lifetime IMaging (FLIM) of Michelangelo s David Presence of organic contaminants absorbed on the marble surface The Fluorescence Lifetime Imaging system has been used for the analysis David face Fluorescence lifetime map (ns) Wax residues, other organic deposits and calcium oxalates are present on the David s face 16

17 In-situ imaging diagnostic techniques Area Imaging / Analysis Reflectance Visible - NIR Hypespectral UV Fluorescence Broadband Hypespectral NON-invasive Fluorescence Lifetime Imaging Digital holography 17

18 Structural diagnostics through holography El Greco: The Baptism, Venice,1567 [ Historical Museum of Heraklion ] Before restoration Holographic Image Double exposure holography Irregularities in the interference fringe pattern distribution reveal active detachments

19 Structural diagnostics through holography El Greco: The Baptism, Venice,1567 [ Historical Museum of Heraklion ] Before restoration Priority list Map Internal detachments Double exposure holography Visible cracks Different material

20 In-situ diagnostic techniques Point Analysis Fibre Optics Reflectance Spectroscopy Visible Fibre Optics Fluorescence Spectroscopy UV Fourier Transform I.R. IR NON-invasive Raman Spectroscopy Visible IR X Ray Fluorescence X-rays 20

21 In-situ diagnostic techniques Point Analysis Fibre Optics Reflectance Spectroscopy Visible Fibre Optics Fluorescence Spectroscopy UV Fourier Transform I.R. IR NON-invasive Raman Spectroscopy Visible IR X Ray Fluorescence X-rays 21

22 Raman Spectroscopy Measure the frequencies of molecular vibrations through inelastic scattering of laser radiation The vibrational spectrum provides the fingerprint of the chemical components of the material e.g. pigment identification

23 Raman analysis of a manuscript of XV century 405 cm -1 Azurite Raman shift (cm -1 ) 23

24 Raman analysis of a manuscript of XV century 253 cm cm -1 Cinnabar 550 cm -1 Minium Raman shift (cm -1 ) 24

25 In-situ diagnostic techniques Point Analysis Fibre Optics Reflectance Spectroscopy Visible Fibre Optics Fluorescence Spectroscopy UV Fourier Transform I.R. IR NON-invasive Raman Spectroscopy Visible IR X Ray Fluorescence X-rays 25

26 Element identification by portable XRF

27 Analysis of paintings (Prof. Longoni, Fiorini) COUNTS Lorenzo Lotto (S.Michele al Pozzo Bianco, Bergamo) K Ca Co Fe K K Analysis of the blue blanket by means of XRF with with SDD detector Ar K K S K K K Mn K Ni K W L 1 L ENERGY [ev] K As L 1 K Bi L 1 Sr K The presence of Si, K, Fe e Co allows the identification of the smaltino veneto

28 Verification of autenticity by XRF Counts Barium white BaSO Fresco painting original attribution: XVI century 0 S (K K (K K Ca K L Ba L Energy [kev] K Cr K K K Fe Chromium green Pigments: Courtesy of Antonio Longoni Fe ochre - used since ancient time Cr chrome green used starting from 1860 Ba barium white used starting from the end of XVIII century

29 Elemental mapping by XRF XRF mapping of a Stradivari violin 3cm 1cm 2mm Analysis area

30 Elemental mapping by XRF XRF mapping of a Stradivari violoin Fe Step: 0.5mm X Ray Spot size: 1.2mm FWHM X Ray source: 20kV, 200uA Acquistion time per pixel: 3s # pixels: 20 x 60 = 1200 pixels Dimensions: 3cm x 1cm Total time: 70 minutes

31 Elemental mapping by XRF XRF mapping of a Stradivari violin P Step: 0.5mm X Ray Spot size: 1.2mm FWHM X Ray source: 20kV, 200uA Acquistion time per pixel: 3s # pixels: 20 x 60 = 1200 pixels Dimensions: 3cm x 1cm Total time: 70 minutes

32 Monitoring: the new frontier of conservation Parameters that need monitoring UV VIS Irradiance Relative Humidity Temperature Vibration/shock Colour changes Organic acids Volatile organic Compounds (VOCs) No x, So x, Sulphides Particulates Bacteria and fungi "Intelligence Heritage" multi-sensor system Wireless sensor network (WSN) Great opportunities for nano-microelectronics and ICT technologies are envisaged 32

33 Conclusions Photonics plays a key role in conservation and is ubiquitous in most diagnostic methods, which must be non-invasive and work in-situ Many innovative methods and instruments, which have been developed in EU Laboratories, deserve financial support to become sustainable in the conservation market (low capital intensive) The synergy of Art and Science can foster new business model in cultural tourism Great benefits can be expected for EU that encompasses much the historical heritage worldwide The conservation of our cultural heritage is: a responsibility toward the new generations a great opportunity for the development of societal and economical wellness for the European people 33

34 Thank you very much for your attention

35 Acknowledgements Rinaldo Cubeddu Sara Bellei LASERLAB-EUROPE Infrastructure (Access program) CUSBO: Centre for Ultrafast Science and Biomedical Optics, Milan, Italy UFL: UV Laser Facility FORTH, Heraklion, Greece 35

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