PIXE Analysis for the pigment identification in the Nizet manucript (18th century)

PIXE analysis for the pigment identification in

the Nizet manuscript (18th Century)

Mélanie Machowski

_{, Helena Calvo del Castillo}

_{, Cécile Oger}

_{, Grégoire Chêne}

_{, David Strivay}

1 _{Centre Européen D’archéométrie – I.P.N.A.S. Université De Liège, Belgium.}

2 _{Bibliothèque Générale De Philosophie Et Lettres, Université De Liège, Belgium.}

Contact email: mmachowski@doct.ulg.ac.be

INTRODUCTION

Written in 1740, the Nizet Manuscript is a heraldry book compiling the genealogy of the Nizet family (Verviers, Belgium). It presents a large number of hand-painted heraldries in traditional heraldic colours; the gold- and silver-like colours have undergone alteration and induced the degradation of the paper. The aims of the study of the manuscript were to identify the palette used and to explain the degradation phenomenon due to the metallic colours.

PRELIMINARY RESULTS

The Nizet manuscript has been first inspected with a binocular lens and UV-visible spectroscopy before doing PIXE analysis. The following colour groups have been distinguished after these preliminary analyses: blue (2 types of pigment), green (2 types of pigment), red (2 types of pigment), pink, brown, grey, black, gold-like pigment and silver-like pigment.

These preliminary results have led to the selection of representative points to be studied by PIXE analysis: 77 points have been choosen among 27 pages of the manuscript to do qualititative and semi-quantitative analyses.

Acknowledgments: Aymeric Holsbeek, Mathieu Clar, Saïd Rakkaa (IPNAS technicians), Thomas Dupuis and Grégoire Chêne (colleagues).

50 100 150 200 250 1 10 100 1000 Inte nsité ( nomb re d e coup s/canal) Canaux Na Mg Al Si S K Cl Ar Ca Ca 150 200 250 300 350 1 10 100 1000 Inte nsité ( nomb re d e coup s/canal) Canaux Fe Cu Cu Channels Counts 150 200 250 300 350 400 1 10 100 1000 Inte nsité ( nomb re d e coup s/canal) Canaux Cu Fe Fe/Co Zn As Co Zn Channels Counts 50 100 150 200 250 1 10 100 1000 Inte nsité ( nomb re d e coup s/canal) Canaux Cl K Ca Ca Al S Si Counts 50 100 150 200 250 1 10 100 1000 Inte nsité ( nomb re d e coup s/canal) Canaux Fe Ca Ca K S Cl Al Si Na Mg Channels Counts 200 250 300 350 400 450 1 10 100 1000 10000 100000 Inte nsité (nomb re d e coup s/canal) Canaux Hg Hg Hg Hg Channels Counts 200 250 300 350 400 450 1 10 100 1000 10000 Inte nsité ( nomb re d e coup s/canal) Canaux Pb Pb Pb Pb Channels Counts 50 100 150 200 250 300 1 10 100 1000 Inte nsité (nomb re d e coup s/canal) Canaux Mn Fe Fe Ca Ca K Si S Al Mg P Channels Counts

EXPERIMENTAL CONDITIONS

The PIXE measurements were performed with the cyclotron of the Institute of Nuclear and Atomic Physics and of Spectrometry of the University of Liege (Belgium). A new specific support has been designed to hold up the manuscript.

Experimental :

• 3.12 MeV proton beam with i ≤ 0.5nA and beam Φ = 0.8mm • Working distance = 13mm.

• 2 detectors, each at 40° to beam direction :

- Si(Li) Sirius e2V detector (low energy) supplied with He flux

- Ultra LEGe GUL0035P Canberra with 50µm Al absorber (high energy) • Acquisition time : 15 min

Lapis-lazuli + azurite ?

(Na, Ca)₈(AlSiO₄)₆(SO₄, S, Cl)₂ + 2CuCO₃.Cu(OH)₂

Prussian blue + smalt ?

(Fe₄(Fe[CN]₆)₃) + glass containing cobalt

Green copper pigment Green copper pigment

CONCLUSIONS

Pigment identification

Some pigments have been clearly identified (vermilion, umber, brass-based, silver-based and tin-based pigments),

while the others are still assumptions (lapis-lazuli + azurite, Prussian blue + cobalt, green copper pigments, red colorant, white lead, organic black pigment) and need some more investigations .

Pros and cons of the use of PIXE analysis for manuscripts

The study of the Nizet mnuscript has shown there are some advantages and disavantages in using PIXE analysis in the case of manuscripts:

• Pros : non-destructive, non-invasive, multi-elemental information, no sampling preparation, high sensitivity

• Cons : not suitable for organic pigments (light elements not detected), no molecular information, long acquisition time due to the necessity to use low current intensity to study manuscripts.

Future Work

In order to exactly identify all the pigments, Raman analyses need to be done to provide the complete pigment identification of the Nizet manuscript.

White lead + organic black ? 2PbCO₃.Pb(OH)₂ + carbon black

Delayed umber Fe₂O₃ + MnO₂

Umber

Fe₂O₃ + MnO₂

Tin powder pigment (Sn) Silver pigment (Ag) _{Brass powder pigment (Cu + Zn)}

Vermilion

HgS

Lake pigment Organic black pigment

Based on C 50 100 150 200 250 1 10 100 1000 Inte nsité ( nomb re d e coup s/canal) Canaux Channels Counts Al Si K Ca Ca Fe S 50 100 150 200 250 300 1 10 100 1000 Inte nsité ( nomb re d e coup s/canal) Canaux Al Si S _{K Ca} Ca _Mn Fe Fe Mg Channels Counts 200 300 400 500 600 700 800 900 1 10 100 1000 Inte nsité ( nomb re d e coup s/canal) Canaux Zn Pb Zn _{Pb Pb} Sn Sn Cu Channels Counts 200 300 400 500 600 700 800 1 10 100 1000 Inte nsité ( nomb re d e coup s/canal) Canaux Counts Channels Fe Fe Cu Ag Ag 150 200 250 300 350 400 1 10 100 1000 10000 Inte nsité ( nomb re d e coup s/canal) Canaux Fe Cu Cu Zn Zn As As Channels Counts 50 100 150 200 250 300 350 1 10 100 1000 Inte nsité ( nomb re d e coup s/canal) Canaux Counts Channels Al Si S K Ca Ca Fe Fe Cu Cu Cl Ar 50 100 150 200 250 300 350 1 10 100 1000 Inte nsité ( nomb re d e coup s/canal) Canaux Channels Counts Cu K Al _Si Ca P Ca Cu Cu Cl Ar S

NON DEGRADED DEGRADED