easel and mural paintings Andreas Karydas Institute of Nuclear and - - PowerPoint PPT Presentation

XRF analysis of pigments on marble, easel and mural paintings

Andreas Karydas

Institute of Nuclear and Particle Physics NCSR “Demokritos” Agia Paraskevi Athenss, Greece karydas@inp.demokritos.gr

Polychromy on marble, wall-paintings , stone materials, easel painting General approach ✓ Detection of at least one fingerprint pigment element – Pigment identification is modest. XRF is performing elemental analysis! Single at millimeter scale XRF measurement ✓ Detection of two or more fingerprint pigment elements at the same spot – Pigment identification is strong (narrow list of candidates) Scanning micro-XRF or Macroscopic XRF analysis ✓ Local association of two or more fingerprint pigment elements – Pigment identification is strong (narrow list of candidates) Trace element detection may help to discriminate pigments of the same type or to address provenance issues

Outline

Archaeological site of Delos 1873 -

In-situ XRF analyses. Delos

Andreas Karydas, ICTP, Tuesday, 4th June 2019

Papposilène, Délos, Musée

Actual state

Initial state

Andreas Karydas, ICTP, Tuesday, 4th June 2019

Observation

Strategy of the in-situ analyses

Recording Mapping XRF analyses Delos Archaeological Museum National Archaeological Museum in Athens

Andreas Karydas, ICTP, Tuesday, 4th June 2019

Photographic Techniques

✓Raking Light ✓ Macrophotography

✓Infra-red photography

✓Ultraviolet photography

Philippe Collet

Andreas Karydas, ICTP, Tuesday, 4th June 2019

Macro-photography

Délos, Musée, Aphrodite,

Andreas Karydas, ICTP, Tuesday, 4th June 2019

Délos, Musée, Aphrodite

UV Photography

Andreas Karydas, ICTP, Tuesday, 4th June 2019

Artémis Elaphébole, Délos, Musée

The boots of Artemis…

UV Photography

Video-microscope examination

Brigitte Bourgeois, CNRS, Louvre Museum

➢to the structure of the statues’ draperies, which often

• bstructed the access of the beam on the interior parts
• f their folds, where colour was preserved in larger and

more homogeneous areas

Inherent difficulties for the XRF analyses

Andreas Karydas, ICTP, Tuesday, 4th June 2019

X-Ray source & Detector Power supply

Spectrometer Head

XRF portable instrumentation @Delos

Andreas Karydas, ICTP, Tuesday, 4th June 2019

Probe with radioisotope source

Andreas Karydas, ICTP, Tuesday, 4th June 2019

➢to the excessive abrasion of pictorial layers and therefore

the insufficient quantity of pigment to be analysed. Complementarity of the Applied analytical techniques The accurate documentation of traces of polychromy on the status’ surfaces by video optical microscopy allowed for the detection of pigments even in areas where they were entirely invisible macroscopically. In thes cases, the combination of the two techniques (XRF and optical microscopy) applied in-situ proved to be highly efficacious.

Inherent difficulties for the XRF analyses

Andreas Karydas, ICTP, Tuesday, 4th June 2019

Delian Raw Pigments

Egyptian Blue Ochre Organic Jarosite Orpiment Ochre Ochre Ochre Ochre Sulfur Flower Sulfur Organic Black Orpiment Celadonite Celadonite

Andreas Karydas, ICTP, Tuesday, 4th June 2019

Orpiment (As2S3) vs Realgar (α-As4S4)

XRD peak: 4th order (120), 2nd order (320, 141) XRD peak’s: 3rd order (111), 4th order (020)

2 4 6 8 10 10 12 12 14 14

10 10 10 10

1

10 10

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10 10

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15 k kV DP DP2 DP DP1 Fe Fe Ba Ba S As As As As Ca Ca coun unts ts/ch /channel X-ray E Energy (k (keV)

2 4 6 8 10 10 12 12 14 14

10 10 10 10

1

10 10

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10 10

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DP DP Fe Fe As As As As Fe Fe S coun unts ts/ch /channel X-ray E Energy (k (keV)

As: 64.6% S: 32.8% Ca: 2.3 % Fe: 0.30 % As: 71.7 % S: 26.7 % Fe: 1.6 %

Andreas Karydas, ICTP, Tuesday, 4th June 2019

Crystallized vs “Amorphous” orpiment

2 4 6 8 10 10 12 12 14 14

10 10 10 10

1

10 10

2

10 10

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10 10

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As As 15 k kV S As As coun unts ts/ch /channel X-ray E Energy (k (keV)

2 4 6 8 10 10 12 12 14 14

10 10 10 10

1

10 10

2

10 10

3

15 k kV DP DP2 DP DP1 Fe Fe Ba Ba S As As As As Ca Ca coun unts ts/ch /channel X-ray E Energy (k (keV)

As: 64.6% S: 32.8% Ca: 2.3 % Fe: 0.30 % As: 64.7 % S: 35.3 %

Andreas Karydas, ICTP, Tuesday, 4th June 2019

Yellow Raw pigments: Jarosite vs Yellow ochre

αFeO-OH+Ca-comp KFe3(SO4)2(OH)6 + Ca-comp + geothite?

2 4 6 8 10 10 12 12 14 14

10 10 10 10

1

10 10

2

10 10

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10 10

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Fe Fe 15 k kV K S Fe Fe Ca Ca coun unts ts/ch /channel X-ray E Energy (k (keV)

2 4 6 8 10 10 12 12 14 14

10 10 10 10

1

10 10

2

10 10

3

Fe Fe 15 k kV Fe Fe Ca Ca coun unts ts/ch /channel X-ray E Energy (k (keV)

Fe2O3: 53.5 % SO3 : 27.9 % K2O : 2.0 % CaO : 1.9 %

Andreas Karydas, ICTP, Tuesday, 4th June 2019

Green Raw Pigment: Celadonite

K(Mg,Fe)(Fe,Al)Si4O10(OH)2 + Ca-compound SiO2 : 53.1 % Fe2O3: 16.9 % K2O : 7.1 % CaO : 8.8 %

2 4 6 8 10 10 12 12 14 14

10 10 10 10

1

10 10

2

10 10

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10 10

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Si Si K Fe Fe Ca Ca coun unts ts/ch /channel X-ray E Energy (k (keV) 15 k kV

Andreas Karydas, ICTP, Tuesday, 4th June 2019

Egyptian Blue raw pellets

CuCaSi4O10 + interstitial glass + residual glass Very interesting the presence of Pb and Sn. Leaded bronze as a source

• f copper?

Using SEM with back scattered electron imaging Pb and Sn were found in association with a second phase (apart the pure Egyptian Blue phase) consisted of interstitial

• glass. (Kakouli, 2002)

The inclusion of leaded glass in the pellets is a unique feature that chronologically agrees with the first occurrence of Ptolemaic leaded glass and glazed faience

4 8 12 12 16 16 20 20 24 24 28 28

10 10

1

10 10

2

10 10

3

40 k kV

Pb Pb Pb Pb Sn Sn Pb Pb Cu Cu Sn Sn Fe Fe RhK hK Ca Ca coun unts ts/ch /channel X-ray E Energy (k (keV)

Andreas Karydas, ICTP, Tuesday, 4th June 2019

Organic Pink Raw Pigment

2 4 6 8 10 10 12 12 14 14

10 10

1

10 10

2

10 10

3

15 k kV Al Al Si Si RhL hL As+Pb Cu Cu Fe Fe Ca Ca coun unts ts/ch /channel X-ray E Energy (k (keV)

2 4 6 8 10 12 14 16 18

10

1

10

2

10

3

40 kV Sr Ni

*

Zn Cu As+Pb Pb Sr Fe Pb Br+As Ca counts/channel X-ray Energy (keV)

Andreas Karydas, ICTP, Tuesday, 4th June 2019

✓The presence of Al and Si, the absence of any other inorganic mineral

pigment provide enough evidence’s in order to characterise it as an

• rganic colorant.

✓Trace elements (except Sr) exhibit large inhomogeneities

Concentrations are expressed in μg/g: Fe: 1140 ± 380 Cu: 220 ± 100 Zn: 109 ± 50 As: 555 ± 253 Br: 95 ± 60 Sr: 276 ± 26 Pb: 643 ± 114 Large variations between elements (etc, As/Pb: 0.5 – 1.6)

✓The presence of Bromine which may support an hypothesis for the

dye’s possible origin from shellfish-murex purple

Organic Pink Raw Colorant

Andreas Karydas, ICTP, Tuesday, 4th June 2019

2 4 6 8 10 12 14 16 18 20 22 24

10 10

1

10

2

10

3

Rh-K lines Artemis A4126/Marble surface Sr Fe Ca

counts/channel

X-ray Energy (keV)

XRF spectrum of the marble substrate

Andreas Karydas, ICTP, Tuesday, 4th June 2019

Polychromy on marbles: The “palette’s”

• 1. Pure pigments
• 2. Mixture of pigments
• 3. Superimposition of different pictorial

layers Natural inorganic Synthetic inorganic Organic based colorants

Andreas Karydas, ICTP, Tuesday, 4th June 2019

Natural occurred pigments

The palette, 1 : “Pure” colours

2 4 6 8 10 12 14 16 18

10 10

1

10

2

10

3

Cu Pb Sr Fe Pb Ca counts/channel X-ray Energy (keV) A1298

Red-Ochre

Andreas Karydas, ICTP, Tuesday, 4th June 2019

Délos, Musée, Stèle de Kerdon

2 4 6 8 10 12 14 16 18 10 10

1

10

2

10

3

Ti Deep Yellow Zn Rb Zr Pb Fe Sr Fe Ca

counts/channel X-ray Energy (keV)

A3473-Aphrodite Head-Terracota

The palette, 1 : “Pure” colours

Natural occurred pigment Yellow Ochre

Délos, Musée, Hermès, A 4256

2 4 6 8 10 12 14 16 18 10 10

1

10

2

10

3

Pb Pb Cu Sr Fe Cu Ca counts/channel X-ray Energy (keV) Papposilene

2 4 6 8 10 12 14 16 18 10 10

1

10

2

10

3

10

4

Zr Pb Zn Pb Fe Sr Fe Ca counts/channel X-ray Energy (keV) Artemis - A4126

The palette, 1 : “Pure” colours

Natural occurred pigments, Malachite/Green Earth Malachite is characterized by its angular particle form. The colour of the coarser particles show high relief and dark edges, while the finer particles are nearly colourless

Artificial pigment

Lead White

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1

10

2

10

3

Pb Pb Pb Pb Pb Ca counts/channel X-ray Energy (keV)

The palette, 1 : “Pure” colours

(PbCO3)2·Pb(OH)2

Andreas Karydas, ICTP, Tuesday, 4th June 2019

❖Its use is attested on other stone monuments of the late Classical and early Hellenistic period.

Function of Lead White

✓To create a homogeneous and non porous undercoat which serves as a substrate to the pictorial layers ✓To increase the colours’ luminosity, thanks to its hiding properties and high refractive index, compared to other whites used in antiquity. ✓ To be used in mixtures with other colours to achieve tonal variations ✓ To be used as a filler mixed with other pigments

Andreas Karydas, ICTP, Tuesday, 4th June 2019

Pb5(VO4)3Cl, V:10.8% Cl: 2.5% Pb : 73.1% The palette, 1 : “Pure” colors Vanadinite Vanadinite has been also found

• n Alexandria stele’s,

Louvre Museum. Natural occurred pigment!

2 4 6 8 10 12 14 16 18 10 10

1

10

2

10

3

Pb V Pb Pb Pb Fe Cu Sr Fe Pb Ca counts/channel X-ray Energy (keV) A4126

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

10 10

1

10

2

10

3

10

4

Rh-L V Pb Cu Fe Ca counts/channel X-ray Energy (keV) A4126

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

10

1

10

2

10

3

10

4

15 kV Pb V Pb Pb Fe Ca counts/channel X-ray Energy (keV) La petite Herculaise

Isis (?), Délos, Musée, Inv. A 5294

The palette, 1 : “Pure” colours Organic colorant Natural occurred pigments

Aphrodite

Andreas Karydas, ICTP, Tuesday, 4th June 2019

2 4 6 8 10 12 14 16 18 10 10

1

10

2

10

3

10

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Zn Pb Pb+As Zr As Pb Pb Cu Sr Fe Ca counts/channel X-ray Energy (keV)

Presence of As: Indicates common origin for pigment lump and pinkish areas on the sculptures

The palette, 1 : “Pure” colours

Pink

• rganic

colorant

Andreas Karydas, ICTP, Tuesday, 4th June 2019

Délos, Musée Apollon,

• Inv. A 4135

The palette, 1: “Pure” colors

Artificial pigment Egyptian Blue

Identification of Egyptian Blue in Ancient pictorial surface’s

Problems : Detection of Si and Sn in Egyptian Blue ✓The poor preservation of Egyptian Blue, due to its high grain size and sandy texture, often enhances the pulverisation

• f the pictorial layer.

➢ The relatively large spot area of the exciting beam results to small contribution in the XRF spectrum by the pigment characteristic X-rays of pigment elements.

Andreas Karydas, ICTP, Tuesday, 4th June 2019

Identification of Egyptian Blue

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10

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10

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Pb 15 kV Si Pb Cu Cu Fe Ca counts/channel X-ray Energy (keV)

Egyptian Blue on Sculpture Raw Egyptian Blue pigment

Andreas Karydas, ICTP, Tuesday, 4th June 2019

What Egyptian Blue pigment was applied? ❖Cu/Pb Ratio approach:

The ratio Cu/Pb is varied between 2.5 - 6 (for the four raw samples)

5 10 15 20 25 30 10 10

1

10

2

10

3

10

4

40 kV

Egyptian Blue on Sculpture Raw Egyptian Blue pigment

Sn Pb Sr Rh-K Cu Pb Fe Pb Ca counts/channel X-ray Energy (keV)

➢The high Cu/Pb ratio

value that was measured, despite the presence of lead white, suggests that raw Eg. Blue pellets with leaded glass were not used on the sculptures.

? ?

Andreas Karydas, ICTP, Tuesday, 4th June 2019

2 4 6 8 10 12 14 16 18

10 10

1

10

2

10

3

10

4

Cu Pb Pb Cu Sr Fe Ca

counts/channel

X-ray Energy (keV) A6323

The palette, 2 : Mixtures

Green-Blue

Andreas Karydas, ICTP, Tuesday, 4th June 2019

Pink Organic colorant + Egyptian Blue

Mauve

XIX IX, 62

Aphrodite, Délos, Musée,

• Inv. A 4200

2 4 6 8 10 10 12 12 14 14 16 16

10 10 10 10

1

10 10

2

10 10

3

40 k kV Pb Pb As As

Cu Cu

Cu Cu Pb+As Fe Fe Pb Pb Ca Ca

count counts/chan /channel el

X-ray E Energy (k (keV)

The palette, 2 : Mixtures

Andreas Karydas, ICTP, Tuesday, 4th June 2019

Délos, Musée, Inv. A 4123

Papposilène

Andreas Karydas, ICTP, Tuesday, 4th June 2019

The palette, 3 : Superimposition of pictorial layers Organic colorant onto Lead White

Andreas Karydas, ICTP, Tuesday, 4th June 2019

Tychè, Délos, Musée, Inv. A 4129

XXII, I, 93

The palette, 3 : Superimposition of pictorial layers

Egyptian Blue onto Organic colorant onto Lead White

Andreas Karydas, ICTP, Tuesday, 4th June 2019

Type/ Description No of Samples No of Samples Pigments Materials identified Raw materials 23 23 Yellow/Brown//Red/Orange Ochre, Egyptian Blue, Orpiment, Realgar, Jarosite, Celadonite, Pink organic, Organic black Sculptures 28 184 Egyptian Blue, Lead white, Yellow/Red/Orange/Brown ochre’s, Vanadinite, Organic colorant, Malachite, Celadonite, Gold Terracotas 3 20 Egyptian Blue, Lead white Yellow/Red/Orange ochre’s, Oragnic colorant, Gold, Carbon Black

Summary of results

Andreas Karydas, ICTP, Tuesday, 4th June 2019

Apollon, Délos, Musée, Inv. A 4135 Laurent Blaise

Andreas Karydas, ICTP, Tuesday, 4th June 2019

Artémis Elaphébole, Délos, Inv. A 449 Laurent Blaise

Andreas Karydas, ICTP, Tuesday, 4th June 2019

Bibliography

❑ Brigitte Bourgeois, Philippe Jockey, Andreas Karydas, “New researches on Polychrome Hellenistic Sculptures in Delos, III: the Gilding processes. Observations and Meanings”, Interdisciplinary studies on Meditteranean Ancient Marble and Stones, sous la direction de Philippe Jockey, Proceedings of the VIIIth International Conference of the Association for the Study

• f Marble and Other Stones used In Antiquity (ASMOSIA), Aix-en-

Provence, 12-18 juin 2006, pp 645 661, 2009 ❑ A.G. Karydas, H. Brecoulaki, B. Bourgeois and Ph. Jockey, “In-situ XRF Analysis of raw pigments and traces of polychromy

• n Hellenistic sculpture at the Archaeological museum of Delos”
• Y. Maniatis (ed.), ASMOSIA VII, The Study of Marble and Other

Stones in Antiquity – Proceedings of the 7th International Conference of the Association for the Study of Marble and Other Stones in Antiquity, BCH Suppl., 51, (2009) 811-829

Andreas Karydas, ICTP, Tuesday, 4th June 2019

Brigitte Bourgeois Philippe Jockey

École française d’Athènes Centre de recherche et de restauration des musées de France

Acknowledgements

Andreas Karydas, ICTP, Tuesday, 4th June 2019

Hariklia Brecoulaki

Thank you for your attention!