How the Electromagnetic Spectrum can be used to Examine Art

Transcription

1 How the Electromagnetic Spectrum can be used to Examine Art HAA th January 2012 Narayan Khandekar Senior Conservation Scientist

2 Electromagnetic Spectrum A continuum of radiation (approx values) IR 1,000, nm Visible nm UV nm X-rays 10nm-0.01nm

3 1. Infrared radiation

4 Infrared spectroscopy

5 IR vibrations

6 IR spectra of Media IR spectra of Pigments

7 FTIR of a cross section to determine the nature of a protrusion growing in the paint layers.

8 Infrared reflectography Infrared radiation is used to illuminate an object. The IR radiation passes through the paint and is absorbed by carbon based pigments as well as metalpoint, and the reflected IR light is recorded in an IR sensitive camera. It is most commonly used to record underdrawing.

9 Garvagh Madonna. Raphael. Infrared reflectogram

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11 Detail of a painting in the Detroit Institute of Arts by Jan Provoost (16 th century) showing changes between the underdrawing and the composition.

12 Fig. 8. Arrest of Christ, circa 1520 A. Photograph. Painting dimensions are 33.8 x 13.5 cm. B. Infrared photograph showing macroscopic features of the underdrawing, with regions of interest indicated by red boxes. C. Enlarged view of first region of interest, showing the location of the first underdrawing feature. D. Enlarged view of the second region of interest, showing the locations of the second and third underdrawing features.

13 Green Target. Jasper Johns MoMA IRR detail from the centre of Green Target Pages from: Suzanne K. Langer s Philosophy in a new key, Chapter entitled: On Significance in Music. Opening line: What distinguishes a work of art from a mere artifact?

14 2.Visible Light

15 Visible Light

16 Visible light Polarised light microscopy Azurite Malachite Malachite x-polars Reflected/Specular light microscopy

17 Visible light Microscopy

18 Azurite Prussian Blue Ultramarine

19 Recording the position of measurement 23. The spectral reflectance of measurement 23. This curve indicates cobalt blue

20 Ultraviolet Radiation

21 Ultraviolet Light Alameda Theatre, TX Visible light UV light

22 Madonna and Child, Jan Muller, Dutch

23 Ultraviolet radiation UV illumination of a painting by Guercino showing retouching.

24 Taddeo Di Bartolo 14 th Century

25 UV Spectroscopy Note that all of these have conjugated double bonds, which gives them their colour

26 UV light can be used to excite Pi electrons from their bonding to anti-bonding state. This occurs at specific wavelengths for the type of bond and that wavelength is absorbed.

27 Chromophore Example Excitation λ max, nm ε Solvent C=C Ethene π > π* ,000 hexane C C 1-Hexyne π > π* ,000 hexane C=O Ethanal n > π* π > π* ,000 hexane hexane N=O Nitromethane n > π* π > π* ,000 ethanol ethanol C-X X=Br X=I Methyl bromide Methyl Iodide n > σ* n > σ* hexane hexane

28 UV absorption UV fluorescence

29 X-ray Radiation

30 X-radiography

31 Feast of the Gods. Giovanni Bellini and Titian, NGA.

32 Perseus and Andromeda. Titian. Wallace Collection.

33 Predella from the Santa Croce Altarpiece by Ugolino di Nero. The altarpiece was disassembled, sawn apart, and sold. Wood grain was aligned in the x-rays to determine the original order of the predella on the altarpiece.

34 X-ray Fluorescence (Energy Dispersive) Fluorescent x-rays X-ray from tube

35 XRF spectrometer

36 Non-destructive method to analyse the metals in pigments. It also can be used to identify alloys used for casting in a semiquantitative way and many other metal objects.

37 Lot and His Daughters. Orazio Gentileschi The Lute Player. Orazio Gentileschi XRF detection of Lead Tin Antimony Yellow

38 XRF applications to photography Stieglitz. Hand of Man. Silver gelatin print Strand. Twin Lakes. Platinum print

39 Bayard Cyanotype

40 The face of a provincial Dutch woman with a covered head is visible in a tritonal color reconstruction of Sb (yellowish white) and Hg (red), underneath the existing 1887 Vincent van Gogh oil on canvas, Patch of Grass. Historians surmise that several years after he gave several original Head paintings to his brother, van Gogh may have come across them again, and painted a bright Parisian grassy landscape over the old-fashioned woman for financial reasons. (Courtesy of TU Delft and KMM Otterlo, NL) XRF Mapping A Cornell University team has demonstrated a novel method for recovering faded text on ancient stone by mapping 2,000-year-old inscriptions using X-ray fluorescence (XRF) imaging

41 X-ray diffraction

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43 Multispectral Imaging

44 Multispectral Imaging Multispectral diagnostic imaging was used to examine Leonardo da Vinci's Adoration of the Magi.

45 Imaging of the Mona Lisa by Leonardo da Vinci

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48 Summary The electromagnetic spectrum can be used to provide information about art. This information can be divided into two broad categories: 1. Visual 2. Spectral This information can be used to understand the physical and historical nature of the art work.