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Uncovering Art Forgery Using Analytical Chemistry

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Real or Fake ' ... Art dealer Otto Wacker put 33 fake Van Goghs on the market ... Said Matter paintings were fakes. Forensic Analysis. Jackson Pollock died in 1956 ... – PowerPoint PPT presentation

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Title: Uncovering Art Forgery Using Analytical Chemistry


1
Uncovering Art Forgery Using Analytical Chemistry
Patricia Munter University of Pennsylvania MCEP
2008
2
Art and Science Meet
  • Many museums house laboratories for materials
    analysis
  • Mainly for restoration and conservation
  • Sometimes materials analysis can authenticate a
    work
  • How can science support the preservation of our
    cultural history?

3
Real or Fake
FAKE
Yesterday this picture was worth millions of
guilders, and experts and art lovers would come
from all over the world and pay money to see it.
Today, it is worth nothing, and nobody would
cross the street to see it for free. But the
picture has not changed. What has?"  Van
Meegeren, 1947 trial for forgery
FAKE
Art dealer Otto Wacker put 33 fake Van Goghs on
the market
Sold for 39.9 million dollars
???
FAKE
FAKE
Hung in a museum for 50 years
Metropolitan Museum paid 50 million dollars
FAKE
Forger was almost sentenced to life in prison
Pretend Picasso
4
How Can a Forgery be Revealed?
  • Artistic style
  • Provenance
  • Scientific Analysis

5
Which is the real Jackson Pollock painting?
New York Times
6
32 Paintings Were Found in This Wrapper
  • Pollock (194649) Tudor City (19401949)
  • 32 Jackson experimental works (gift purchase)
    Bad condition.
  • 4 both sides. All
  • drawing boards.
  • Robi paints.
  • MacDougal Alley, 1958.

7
Paintings and Provenance
8
Expert Opinion
  • Ellen Landau
  • Art scholar, Case Western University
  • Expert on authentication of works by Pollock
  • Thought Matter paintings were authentic
  • Francis OConnor
  • Compiled Catalogue Raisone of Pollocks works
  • Said Matter paintings were fakes

9
Forensic Analysis
  • Jackson Pollock died in 1956
  • Analysis of materials can inform
  • Pigments have a known history

10
Pigments as Historic Artifacts
  • Choice of colorants has changed for artists
    throughout history based on availability
  • Cave paintings of Lascaux, France
  • Minerals used

Photo M. Burkitt 'The Old Stone Age' (1955),
after Breuil
  • Hematite or iron red oxide -Fe2O3
  • Limonite or yellow ocher FeO(OH)nH2O
  • Charcoal or carbon - C
  • Manganese dioxide - MnO2
  • http//www.donsmaps.com/cavepaintings.html

11
More Colored Minerals
  • Ancient Egyptians ground minerals
  • Red lead (Pb3O4)
  • Malachite (CuCO3)
  • Orpiment (As2S3)
  • Manufactured Egyptian Blue first synthetic
    pigment
  • (CaCuS4O10)

12
Preparation of More Pigments Devised
  • Lead white - lead(II) carbonate
  • PbCO3
  • Verdigris copper(II) acetate
  • Cu(CH3COO)2
  • Ultramarine blue (1828)
  • (Na8-10Al6Si6O24S2-4)

13
Mauve First Artificial Organic Dye
  • Synthesized in 1856 by the 18 year old William
    Perkins
  • He was trying to make quinine from coal tar
  • Mixed aniline, toluidine and methanol started
    an industry

http//ce.t.soka.ac.jp/chem/iwanami/intorduct/ch11
synthesis.pdf
14
Color Index
  • 12000 products with 1700 generic names
  • All products are given a color index unique
    identifier
  • 10 pigment codes PB, PBk, PBr, PG, PM, PO, PR,
    PV, PW, PY
  • Constitution number sequential number given as
    new pigments are added to the index

15
Colored Compounds
  • Variety of structural characteristics will make a
    compound appear colored
  • Fundamental similarity all capable of absorbing
    selected wavelengths of light
  • When light is absorbed, electrons go to higher
    energy levels
  • Energy of the transition determines wavelength
    that is subtracted
  • Color we see are wavelengths not absorbed

16
Color Perceptionhttp//www.chem.purdue.edu/gchelp
/cchem/color2.html
  • Color absorbed
  • Red -------------------------?
  • Orange --------------------?
  • Yellow ---------------------?
  • Lemon Yellow -----------?
  • Green ----------------------?
  • Blue-green ----------------?
  • Blue ------------------------?
  • Indigo ----------------------?
  • Violet -----------------------?
  • Color seen
  • Blue-green
  • Blue
  • Indigo
  • Violet
  • Purple
  • Red
  • Orange
  • Yellow
  • Lemon Yellow

17
Color of Inorganic Pigments
  • Ligand field effects (iron oxide reds and
    yellows)
  • Charge transfer (chromates and ultramarines)
  • Pure semi-conductors (cadmium yellows and
    oranges)

18
Coordination Compounds
  • Metal atom or ion surrounded by ligands
  • Crystal field theory explains splitting of d
    orbitals due to influence of ligands
  • Excitation of electrons from one d level to
    another

Chang, 2002
19
Charge Transfer
  • An electron moves from one atom to another in a
    compound
  • In Prussian blue
  • Fe(II) reduces Fe(III) and it is oxidized to
    Fe(III)
  • Fe(III)4Fe(II)(CN)63xH2O

Simple cubic lattice of Prussian blue. Fe(II)
yellow Fe(III) red C gray N blue
Ware, 2008
20
Semiconductor
  • Vermillion (HgS) and Cadmium yellow (CdS)
  • Forbidden energy level in between allowed levels
    - called a band gap
  • If an electron is promoted to the conduction
    band, all the energies above the conduction band
    are absorbed

http//www.nanolytics.de/index.php?lgenmainfiel
d_of_businesssubwhy_colloids
21
Absorbance - Charge Transfer Versus Semiconductor
  • Charge transfer absorbs a narrow wavelength
  • If green is absorbed, colors on either side will
    be reflected
  • Red and blue will be seen, therefore the color
    seen is purple
  • Semiconductors absorb a band of color
  • If green is absorbed, all colors with higher
    frequency than green will be absorbed (green and
    blue)
  • Yellow and red reflected, therefore orange will
    be seen

22
Conjugated Double Bonds
  • p electrons delocalized over length of the
    conjugation
  • Particle on a line model can be used to calculate
    the transition energy from the ground state to
    the excited state

Methylene blue http//omlc.ogi.edu/spectra/mb/inde
x.html
23
Pigments and Paints
  • Technically- artists use paints
  • Paints consist of 4 parts which may interfere
    with each other in an analysis
  • Pigment(s)
  • Medium or binder for suspension
  • Diluent
  • Additives

24
Methods of Analysis Complement One Another
  • Fourier Transform Infrared Spectroscopy (FTIR)
  • Raman Spectroscopy
  • Laser Desorption Time of Flight Mass Spectrometry
  • Pyrolysis Gas Chromatography/ Mass Spectrometry
  • Scanning Electron Microscope / Energy Dispersive
    X-Ray Analysis

25
IR versus FTIR
  • IR
  • IR Spectroscopy uses the absorption of infrared
    light measured as a function of wavelength to
    identify molecular compounds
  • Vibrations that make changes in dipole moment are
    observed
  • Spectrum is like a fingerprint
  • FTIR
  • Two mirror system
  • One stationary, one pulses in coordination with
    laser
  • Light source is split into 2 beams which go to
    the 2 mirrors then are directed back to splitter
  • When beams combine, it is an interferogram
  • Interferogram is directed at the sample
  • Some energy is absorbed, transmitted energy is
    read by detector
  • Data from detector is modified using an algorithm
    known as a Fourier transform

26
  • Dispersive IR
  • Monochromator
  • Diffraction grating or prism
  • Breaks light into individual frequencies
  • Slow scanning speed

http//www.umaine.edu/misl/ft_spectrometer.html
27
Raman Spectroscopy
  • Raman effect refers to small amount of light that
    scatters inelastically from a molecule, at a
    different wavelength than the incident light
  • This absorbed energy is an intrinsic property of
    the molecule, independent of the incident
    wavelength
  • Raman instruments use lasers, wavelength chosen
    to give best signal to noise ratio.
  • Advantage of Raman - New instruments allow one to
    do analysis without any destruction of the sample

28
Mass Spectrometry
  • Fragments molecules into ions using one of a
    number of techniques
  • Fragments are separated on the basis of mass to
    charge ratio (m/z) by magnetic or electric field
  • Molecular weight of the compound and mass of
    major ions gives information that helps elucidate
    the structure

29
Mass Spec Systems Used for Art Analysis
  • LDI-TOF-MS
  • Laser desorption volatilizes and fragments the
    molecule
  • No sample preparation only very small sample
    needed
  • Time of flight refers to the detection system
    that relies on the time it takes to reach the
    detector correlating with the molecular weight
  • Py-GC-MS
  • Used for large molecules
  • Generally used for polymer analysis
  • Volatilizes sample by rapid heating on platinum
    wire, then sample is introduced into from a GC

30
SEM/EDX
  • Useful for analyzing a pigment with a limited
    number of elements
  • High energy electromagnetic radiation directed at
    sample
  • Beam dislodges electron from sample
  • Higher energy electron from sample replaces
    missing electron and photon is released
  • Energy of photon is measured to determine
    elemental source of emission

http//www.geosci.ipfw.edu/sem/semedx.html
31
Harvard University Art Museums
  • Three works thought to be by Jackson Pollock
    (1912-1956) and owned by Alex Matter were
    analyzed using a variety of techniques to
    determine age and composition of materials

32
Raman and SEM/EDX
http//www.artmuseums.harvard.edu/home/HUAMreport0
12907.pdf
33
LDI-TOF Mass Spectrometry
http//
www.artmuseums.harvard.edu/home/HUAMreport012907.p
df
34
Fourier Transform IR
http//www.artmuseums.harvard.edu/home/HUAMreport0
12907.pdf
35
PR254 Diketopyrrolo-Pyrrole (DPP) Pigment
Herbst, 2004
36
PR254 Mass Spectrometry Spectrum
Sodiated and di-sodiated species
Loss of CO
Wyplosz
37
Mass Spectrum of Paint from a Car Fender Panel
Shows presence of both Quinacridone Red ( MW 312)
and PR254 (MW 356)
Stachura, et al., 2007
38
FTIR Spectrum of PR254 in Car Paint of Suspected
Vehicle and Damaged Bumper
Suspected hit and run vehicle
Damaged car bumper
Reference sample of PR254
Buzzini, et al., 2006
39
Raman Spectra Comparing Paint from a Damaged
Bumper and a Suspected Vehicle
Damaged Car Bumper
?exc 785 nm
Suspected Hit and Run Vehicle
PR254 was identified, due to its Raman bands.
Buzzini, et al., 2006
40
Pyrolysis GC Mass Spectrometry
http//www.artmuseums.harvard.edu/home/HUAMreport0
12907.pdf
41
Conclusions
  • Pigment analysis is useful for authentication of
    art works and new analytical techniques are
    improving the analyses
  • Databases of spectra are needed for pigment data
  • Even with objective scientific data, experts from
    the art world are not in agreement over the
    Matter paintings

42
  • References
  • Adar, F. Raman Applications That Are Driving a
    Rapidly Expanding Market. Spectroscopy. 2008, 23,
    24-29.
  • Brill, T.B., Why Objects Appear as They Do. J.
    Chem. Educ. 1980, 57, 259-263.
  • Buzzini, P., Massonnet, G., Sermier, F.M., The
    Micro Raman Analysis of Paint Evidence In
    Criminalistics Case Studies. J. Raman.
    Spectrosc. 2006, 37, 922-931.
  • FT-IR vs. Dispersive Infrared Theory of Infrared
    Spectroscopy Instrumentation. http//www.thermo.
    com/eThermo/CMA/PDFs/Product/productPDF_21615.pdf
    (accessed 7/5/08).
  • Gardner, C.W. Annual James L. Waters Symposium at
    Pittcon Raman Spectroscopy. J. Chem. Educ.
    2007, 84, 49.
  • Gettens, R.J. Painting Materials A Short
    Encyclopedia Dover Publications Inc. New York,
    1966
  • Hao, Z., Iqbal, A. Some Aspects of Organic
    Pigments, Chem. Soc. Rev. 1997, 26, 203-213
  • Herbst, W. Industrial Organic Pigments
    Wiley-VCHWeinheim, Germany, 2004.
  • Jones-Smith, K., Mathur, H., Revisitng Pollocks
    Drip Paintings, Nature 2006, 444, E9-E10.
  • Kennedy, R., Drip Wars A Pollock, in the Eyes of
    Art and Science. The New York Times.
    http//www.nytimes.com/2007/02/04/weekinreview/04
    kennedy.html?_r2ei5088ene789e7aoref
    (accessed 7/9/08).
  • Kincade, K. Laser-based Instrumentation Sheds New
    Light on Old Art. Laser Focus World. 2008, 44,
    85-89.
  • Orna, M.V. Chemistry and Artists Colors Part I.
    Light and Color. J. Chem. Educ. 1980, 57,
    256-258.
  • Orna, M.V. Chemistry and Artists Colors Part
    III. Preparation and Properties of Artists
    Pigments. J. Chem. Educ. 1980, 57, 267-269.
  • Orna, M.V. Chemistry, Color, and Art. J. Chem.
    Educ. 2001, 78, 1305-1311.Papson, K., Stachura,
    S., Boralsky, L., Allison, J. Identification of
    Colorants in Pigmented Pen Inks by Laser
    Desorption Mass Spectrometry. J. Forensic Sci.
    2008, 53, 100-106.
  • Papson, K., Stachura, S., Boralsky, L., Allison,
    J. Identification of Colorants in Pigmented Pen
    Inks by Laser Desorption Mass Spectrometry. J.
    Forensic Sci. 2008, 53, 100-106.
  • Schulte, F., Brzezinka, K., Lutzenberger, K.,
    Stege, H., Panne, U. Raman Spectroscopy of
    Synthetic Organic Pigments Used in 20th Century
    Works of Art. J. Raman. Spectrosc. Online 2008,
    Published online in Wiley Interscience.
    (www.interscience.wiley.com).
  • Stachura, S., Desiderio, V.J., Allison, J.
    Identification of Organic Pigments in Automotive
    Coatings Using Laser Desorption Mass
    Spectrometry. J. Forensic Sci. 2007, 52,
    595-603.
  • Technical Analysis of Three Paintings Attributed
    to Jackson Pollock. http//www.artmuseums.harvar
    d.edu/home/HUAMreport012907.pdf (accessed
    7/9/08).
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