M . P E R E S , F . M . C O S T A & A . G O M E SC e n t r e f o r M o l e c u l a r S c i e n c e s a n d M a t e r i a l s , U n i v e r s i t y o f L i s b o n , P o r t u g a l

M . E . J A R D I MC e n t r e f o r P h i l o s o p h y o f S c i e n c e & C C M M , U n i v e r s i t y o f L i s b o n , P o r t u g a l

T . F E R R E I R A , L . D I A S & J . M I R Ã OC Q E & C G E & H E R C U L E S - C u l t u r a l H e r i t a g e S t u d i e s a n d S a f e g u a r d

C e n t r e , U n i v e r s i t y o f É v o r a , P o r t u g a l

M . L . C A R V A L H OC e n t r e f o r A t o m i c P h y s i c s , U n i v e r s i t y o f L i s b o n , P o r t u g a l

m a r i l i a p e r e s @ c i b e r p r o f . c o m

Analytical studies of 19th century photographs by

non-destructive techniques

International Congress : cience and Technology for the Conservation of Cultural HeritageSantiago de Compostela, 2 – 5 October, 2012

R E S E A R C H P R O J E C T: P T D C / H I S - H C T/ 1 0 2 4 9 7 / 2 0 0 8

F I N A N C E D BY

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SCIENTIFIC PHOTOGRAPHY:STUDY OF INSTRUMENTATION AND CHEMICAL-PHYSICAL

PROCESSES DURING THE PERIOD19TH- EARLY 20TH CENTURIES

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INTRODUCTION Identification of 19th century photographic prints

Visual and microscopic methods of identification

Identification of photographs using non contact and non destructive methods

Qualitative XRF analysis of photographs

Scanning Electron Microscopy coupled with a Energy Disperse Spectrometry (SEM-EDS)

Reflectance Fourier-Transform Infrared Spectroscopy

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Lady portrait (A. Solas)Print G2

Man portrait (A. Solas)Print G1

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19th Century Portuguese Carte-de-Visite

EARLY PHOTOGRAPHICPROCESS IDENTIFICATION

METHODOLOGY

Identification of primary visual clues : name of photographer, date, exhibition or photographic competition labels, logos, etc.

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(A. Solas, c. 1896)

Identification of secondary visual clues: surface topography; tonality and colour of the image layer; presence or absence of fading or deterioration.

Date: c. 1896

Glossy surface; brown tonality; no fading and some deterioration

IDENTIFICATION OF 19TH

CENTURY PHOTOGRAPHICPRINTSPOSSIBLE STRUCTURE

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(A. Solas; c.a. 1896)

Binder layer (image+ toning)

Baryta layer

Card

Protective layer

Paper support

Classification (Reilly; 1986)

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One layer

(no binder layer and

no baryta layer)

Two Layers

(no baryta layer)

Three layers

- Salted paper- Cyanotype- Platinotype

- Albumen print- Carbon print

- Gelatin silver (POP)- Collodion (POP)- Gelatin silver (DOP)

MICROSCOPICEXAMINATION OFPHOTOGRAPHS

Stereoscopic Zoom Microscope

NIKON SMZ1500

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C.C.M.M., Chemistry and Biochemistry Department, Faculty of Sciences, University of Lisbon

(M. Peres, 2011)

• Magnification:10x and 70x

• Illumination: 45º

• Exposure and Gain: constants for each magnification

MICROSCOPIC ANALYSIS10

Protective layer hide paper fibers

Mag. 10x (200ms, 1,2x)

Mag. 70x (600ms, 1,4x)

QUANTITATIVE X-RAY FLUORESCENCESPECTROSCOPY (XRF)

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• X-ray tube (PW 1140; 100 kV, 80 mA) equipped with a changeable secondary target, normally made off molybdenum

• Si (Li) detector, with a 30 mm2 active area and 8 µm beryllium window

• Energy resolution 135 eV at 5.9 keVand the acquisition system is a Nucleus PCA card

• Commercial pulse processor (Oxford).

• The X-ray generator was operated at 50 kV and 20 mA and a typical acquisition time of 1000 s was used

Centro de Física Atómica, U.L.(M. Peres 2011)

EDXRF Spectrometer

QUALITATIVE X-RAY FLUORESCENCE SPECTROSCOPY (XRF)12

- No conclusive analysis regarding silver existence- Significant amount of lead- Possible presence of baryta layer (BaSO4)

Pbl1

SrKα

BaKα

BaKβ1

BaLβ2,15

BaLγ1 Ni

Kα

S Kα

Pbη

PbLα1

PbLβ1

PbLγ1

Scanning Electron Microscopy coupled with Energy Dispersive Spectrometry (SEM-EDS)

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Laboratório HERCULES, Un. Évora(L. Dias, J. Mirão, T. Ferreira, 2011)

Acceleration voltage of 20.0 kV and variable pressure of 50 Pa were used for chemical analysis.

Backscattered electron imaging mode was used.

The surface morphology and homogeneity of uncoated samples were analysed in a HITACHI S-3700N variable pressure Scanning Electron Microscope (SEM-EDS) coupled with a Bruker X-Ray Energy Dispersive Spectrometer used for elemental composition estimation.

• Variable pressure chamber (50 Pa)

• A 20 cm width chamber allows the analysis ofthe entire photograph avoiding microsampling

Laboratório HERCULES, Un. Évora(L. Dias, J. Mirão, T. Ferreira, 2011)

SEM-EDS ANALYSIS14

P1

P2

P4

P5

P3

P6

P7

P8

SEM-EDS ANALYSIS15

- Evidence of silver (no gold detected)- The significant amount of lead is confirmed and points out an enamelled paper- Overall presence of barium indicates a baryta layer

EDS spectrum obtained at the P5 (Print G1)

EDXRF AND SEM-EDS ANALYSIS16

A significant amount of lead is confirmed by both techniques while thepresence of silver was only observed by the EDS examination. The use oflead indicates an enameled print.

No gold was found, confirming a photographic process with silver salts,without gold toning.

The overall detection of barium suggests a baryta layer. Although sulfur wasdetected by XRF, due the large amount of lead (the Kα and Kβ lines of sulfurare superimposed with the Mα line of lead) it is not possible to evaluate byEDS the atomic proportion of both elements in the print.

Strontium and manganese are typical of the silver halide technology ofblack-and-white photographs .

The detection of other elements in the emulsion probably indicates the lowpurity of commercial chemicals used in these historical photographicprocesses.

Fourier-Transform Infrared Spectroscopy17

ALPHA FTIR da BRUCKEROPTIKS , portable spectrometer

Laboratório HERCULES, Un. Évora

• Fourier Transform Infrared Spectrometer

• ALPHA model of Brücker with a reflectance module A241/DVQuickSnapTM and a video camera

• 64 scans with 4 cm-1 resolution

• Diameter of analysis: 6 mm

• The spectra were obtained in the reflectance mode and converted to absorvance mode by the Kramers-Kronigalgorithm.

Fourier-TransformInfrared Spectroscopy

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Comparative spectra analysis of A. Solas sample (G1)and mate collodion test sample (E2)

The IR spectrum comparison was done using the cellulose nitratespectrum in transmittance from Getty Conservation Institute(DERRICK et al 1999).

2922

2853

1741

1643

10041287

856

500100015002000250030003500

% T

Wavenumber/ cm-1

Print G1 Print E2 (collodion)

Fourier-Transform Infrared Spectroscopy

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Results and discussion

The spectrum of the print G1 shows that there issome evidence for collodion (cellulose nitrate)considering the characteristic bands: stretchingband N‐O in the ranges 1660 to 1625 cm‐1 and 1285to 1270 cm‐1; the C‐O bending band at 1300 to 900cm‐1 and the N‐O bending band at 890 to 800 cm‐1

(Cattaneo et al, 2008).The bands occurring at 2922 and 2853 cm-1 are

attributed to the baryta layer (barium sulfate)(Derrick et al, 1999).The band occurring at 1741 cm-1 can be attributed to

castor oil, a plasticizer used in the preparation ofthe collodion emulsion (Cattaneo et al, 2008).

MULTI-TECHNIQUE NON-DESTRUCTIVE APPROACH20

Woodbury (1896)

ENNAMELEDPAPERc. 1896

Silverprocess

No gold Collodion

Barytalayer

Lead

FINAL NOTES21

• The multi-technique analyses allow us to conclude that these photographs arecollodion positives prints with a baryta layer without gold toning; they have alsobeen submitted to a final enamel protection treatment.

• It should be emphasized that SEM-EDS analysis at a low vacuum (50 Pa)observation method gave good reproducible results and enabled the observationof non-conductive samples, such as the photographic prints, avoiding samplepreparation or micro sampling procedures.

• Additionally, in-situ reflectance FTIR spectroscopy revealed itself to be extremelyuseful in probing the nature of the protective layer.

• The surface analyses didn’t detect degradation products which can be attributedto the type of enamel protection that has helped to preserve the prints.

On the overall, the analyses revealed key information about the deterioration status ofthe photographic prints that can be critical to its preservation and restoration, being alsouseful on the identification of fakes or reproductions.

References22

CATTANEO, B., CHELAZZI, D., GIORGI, R., SERENA, T., MERLO; C., BAGLIONO, P. (2008), Physico-chemical characterization and conservation issues of photographs dated between 1890 and1910, Journal of Cultural Heritage, 9, pp. 277-284.

DERRICK, M., STULICK, D. & LANDRY, J. 1999. Infrared Spectroscopy in Conservation Science. LosAngels: The Getty Conservation Institute.

ENYEART, J., ANDERSON, A., PERRON. S., ROLLINS, D., & FERNANDO, Q. (1983). Non-destructiveElemental Analysis of Photographic Paper and Emulsions by X-ray FlorescenceSpectroscopy, History of Photography, Vol. 7, Nº. 2, pp. 99 – 113.

RICCI, C. et al (2007), ATR-FTIR imaging of albumen photographic prints, Journal of CulturalHeritage, 8: 387-395.

STULIK, D. & KAPLAN, A. (2010), An example of complex composite materials and processes:Photography in ARTIOLI, G. (coord), Scientific Methods and Cultural Heritage: An Introduction tothe Application of Materials Science to Archaeometry and ConservationScience, Oxford, University Press, pp. 419-433.

WOODBURY, W. (1896). Enamel paper. In The Encyclopaedic Dictionary of Photography. W.Woodbury. New York, The Scovill & Adams Company of New York, p. 192.

Acknowledgements• FCT- Fundação para a Ciência e Tecnologia

• Ministério da Educação de Portugal

• Anabela Boavida, C.C.M.M, Fac. de Ciências da Un. deLisboa

• José Carlos Frade, Laboratório de Conservação eRestauro José de Figueiredo, Instituto dos Museus e daConservação.

• Nuno Borges de Araújo, Historian ofPhotography, Braga

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Acknowledgements: