Studio analitico sui materiali utilizzati nei dipinti murali della “Camera dell’amore” del Palazzo El Sakakeny
10.6092/issn.1973-9494/7167
Nel presente studio è stata realizzata un’indagine completa su dipinti murali realizzati da studenti italiani e risalenti al XIX secolo, inizialmente situati nel Palazzo El Sakakeny, nell’omonima piazza in Egitto. Gli strumenti analitici utilizzati per l’indagine sui materiali sono stati la Microscopia Ottica, Microscopia Elettronica a Scansione con EDX, Diffrazione a Raggi X e trasformata di Fourier accoppiata con Riflettanza Totale Attenuata (FTIR-ATR). Le analisi hanno rivelato la presenza di pigmenti come ematite, litargirio, ossido di zinco, ossido dioro, goethite (ocra bruna) e malachite utilizzati per la realizzazione delle pitture murali, mescolati con olio di lino o con colla animale. Lo strato di fondo originario comprende ossido di zinco e gesso; il legante utilizzato nel fondo è colla animale, mentre il supporto è costituito da una pietra calcarea.
application/pdf
1973-9494
7167
en
Abubakr Mohamed Moussa
Conservation Science in Cultural Heritage
FTIR
Analytical Study of the Materials Used in Mural Paintings in the Love Chamber of El Sakakeny Palace
Text.Serial.Journal
https://conservation-science.unibo.it/
16
Articles
2017-07-24
2017-07-17
2017-07-24
2017-09-04
127-146
CSCH
Abubakr Mohamed Moussa
2016
10.6092/issn.1973-9494/7167
127
Cairo University
1973-9494
FTIR
en
146
Stuart, B.H.(2007) Analytical techniques in materials conservation, England: John Wiley & Sons Ltd., pp.142-144.
Analytical Study of the Materials Used in Mural Paintings in the Love Chamber of El Sakakeny Palace
https://conservation-science.unibo.it/article/download/7167/6893
16
A     NALYTICAL STUDY OF THE MATERIALS USED IN
      MURAL PAINTINGS IN THE LOVE CHAMBER OF EL
      SAKAKENY PALACE

  Kholod Khairy Salama*4
  National Museum of Egyptian Civilization
  Cairo, Egypt

  Mona Fouad Ali
  Conservation Department
  Faculty of Archaeology, Cairo University, Egypt

  Abubakr Mohamed Moussa
  Conservation Department
  Faculty of Archaeology, Cairo University, Egypt

  Keywords: paintings, El Sakakeny Palace, optical microscope, XRD, FTIR


  1. Introduction

   The 19th century is considered to be the most important period in Egyptian art, and is
distinguished by the great paintings produced by foreigners in the country at that time.
During this century, several mural paintings were executed on the ceilings and walls
of several rooms in a style that differed from the usual oriental one used in Egypt [1].




                                                                                                   CONSERVATION SCIENCE IN CULTURAL HERITAGE
  1.1. Stratigraphic studies

   The first layer of rough coating, applied on the wall support of limestone, is a mortar
composed of a mixture of hydrated lime (calcium hydroxide) and coarse sand. The
second layer consists of zincate and gypsum. The third layer is the pictorial layer,
made of pigments, the medium being applied in several coatings with a brush [2].
In this study, three mural paintings were fully investigated. Besides gaining technical
information about this type of painting, the purpose of this research was to acquire
knowledge about both the organic and inorganic materials used. The study comprised
the examination of the pigments, media and ground layer [3].

  1.2. The examined paintings

   The mural paintings are located in the Love Chamber on the first floor of El Sakak-
eny Palace in El Sakakeny Square. The style is Rococo, as the colours are light and
there is obvious movement in the flight of the birds and in the movement of the planets
(Figure 1). Their dimensions are about 20 x 25 cm, 20 x 45 cm and 20 x 25 cm without
the frame, whose width is 1.8 cm. El Sakakeny Palace dates back to the 19th century.


* Corresponding author: kholodkhairy@yahoo.com


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                                                                                                                         1.3. Conservation state of the paintings

                                                                                                                         The analyses of these paintings were carried out during restoration treatment. From
K.K. Salama, M.F. Ali, A.M. Moussa - Analytical study of the materials used in mural paintings in the love chamber




                                                                                                                      the visual inspection and cross section images, the condition of the paintings is poor,
                                                                                                                      with weakness in the paint layers, which is the most apparent deterioration phenom-
                                                                                                                      enon (Figure 2 A-F).
                                                                                                                         There are several areas of the pictorial layer that have become detached, with chro-
                                                                                                                      matic alterations around the missing parts, grease and soot spots, and detachment of
                                                                                                                      decorative elements.




                                                                                                                      Figure 1. The three mural paintings in El Sakakeny Palace showing sampling points.




                                                                                                                      Figure 2. Condition assessment of the mural paintings: (A) detachment of decorative elements;
                                                                                                                      (B) loss in paint layers; (C-D) soot and grease spots; (E) blistering; (F) cracks.



                                                                                                                         2. Materials and methods

                                                                                                                         2.1. Sampling

                                                                                                                         Samples 1-8 were collected carefully from the damaged edges using a micro scal-
                                                                                                                      pel to identify the constituent materials and degree of deterioration of the paintings. All
                                                                                                                      the analyzed and investigated samples were collected from areas without aesthetic
                                                                                                                      value or from severely damaged parts.

                                                                                                                         2.1.1. Optical Microscope (OM)

                                                                                                                         The samples were examined with an optical microscope to identify their shape and
                                                                                                                      chromatic alterations. In addition, the Optical Microscope helped us identify aspects of
                                                                                                                      the damage within the samples, including the minutest cracks.


                                                                                                                128
   2.1.2. X-Ray Diffraction (XRD)

    The X-ray diffraction patterns of the paintings were obtained using a diffractometer
(Philips PW 1840) operated at 40 kV and 25 mA, using Cu Kα radiation and a receiving
slit of 0.2 mm. Measurements were made at room temperature. Preparation of each
sample consisted of grinding it in the dry form by using a mortar and pestle to obtain
a fine powder.

   2.1.3. Scanning Electron Microscope coupled with EDX (SEM-EDX)

   Samples were analyzed with an Environmental Scanning Electron Microscope
(FEI, Netherlands) coupled with Energy Dispersive X-ray analysis. The microstructure
and morphology of the mineral compounds in the paintings were analyzed with a FEI
Quanta 200 Scanning Electron Microscope. The microscope operated at an accelerat-
ing voltage of 30 kV. Sample preparation consisted in the application of a superficial
gold film by sputtering to prevent electrostatic charge.

   2.1.4. Fourier Transform Infrared - Attenuated Total Reflectance (FTIR-ATR)

   Samples were analyzed with an FTIR spectrometer (Model 6100 Jasco, Japan).
Spectra were obtained in the transmission mode with a TGS detector and using an
ATR crystal which represents (2mm/sec) Ni-Colet 760 added scans at spectral region
ranging from 4000 to 400 cm-1 with a resolution of 4 cm-1.



   3. Results and discussion




                                                                                                     CONSERVATION SCIENCE IN CULTURAL HERITAGE
   3.1. Optical microscope (OM)

   After examining the samples from the paintings, the following observations were
made: the sample of black color was composed mainly of fine to medium-grained
quartz, iron oxides applied as a layer on the ground layer; the reddish brown contained
black spots; the blue color was of a powdery consistency, the deep green color was
applied in multi layers, as was the golden green color (Figure 3A-F).

   3.2. X-ray diffraction (XRD)

   The XRD patterns of the samples from the mural paintings in El Sakakeny Palace
indicate the results resumed in Table 1 and Figure 4.
   XRD analysis results revealed the following:
   The presence of 100% gypsum in sample 1 indicates that the frames of the mural
paintings are made entirely of gypsum.
   The ground layer consists of zincate mixed with gypsum in the ratio 2:1.
   The colors used in the painting were common in that period. The red color is
hematite, the yellow color is litharge, the green color is malachite, the blue color is wol-
lastonite, the golden color is gold oxide and the black color is magnetite. The reddish
brown consists of hematite mixed with azurite in the ratio of 3:1 and the light green
color is a mixture of litharge with malachite and calcite in the ratio of 3:2:1 (Figure 4).


                                                                                               129
K.K. Salama, M.F. Ali, A.M. Moussa - Analytical study of the materials used in mural paintings in the love chamber




                                                                                                                      Figure 3. Optical microscopy shows structure of paintings: (A) crystals of the ground are large
                                                                                                                      and seem to be homogenous; (B) red color mixed with a percentage of fine black color and there
                                                                                                                      are cracks on the paint layer; (C) blue color has a powdery consistency; (D) flecks of white and
                                                                                                                      black appear in the deep green color; (E) the layers of the deep green color; (F) the irregularly
                                                                                                                      applied golden color.


                                                                                                                          Halite constitutes 21% of the ground layer, 19% of the painting layer and 16% of
                                                                                                                      the deep green color sample. The presence of salts determines a major deterioration
                                                                                                                      factor [4] as the growth of salts can cause interior pressure which leads to detachment
                                                                                                                      of the paint layer in mural paintings [5].

                                                                                                                      Table 1. The XRD analysis results of eight samples from the mural paintings at El Sakakeny
                                                                                                                      Palace.
                                                                                                                            Compounds %               1s      2s      3s      4s     5s       6s        7s       8s
                                                                                                                       Gypsum                         100    61.3     --      --     16.5      --      20.1      37
                                                                                                                       Calcite                         --     --      --      --     15       16        --       --
                                                                                                                       Silica                          --    9.5      --      --      --       4        --      6.5
                                                                                                                       Malachite                       --     --      --      --     15       24        --       --
                                                                                                                       Halite                          --     21      19      --     16        --       --       --
                                                                                                                       Albite                          --     6       --      --      --       --       --       --
                                                                                                                       Zincate                         --     --     35.5     35     28.5      --       55       --
                                                                                                                       Hydrocrossite                   --     --      17      14      --       --       --       --
                                                                                                                       Azurite                         --     --     6.5      --      --       --       --       --
                                                                                                                       Litharge                       ---     --      --     17.5     --     47.5       --       --
                                                                                                                       Hematite                        --     --      --      14      --       --      14.9      10
                                                                                                                       Magnetite                       --     --      --      --      --       --      45.8     10.8
                                                                                                                       Wollastonite                    --     --      --     11.8     --       --       --       --
                                                                                                                       Anhydrite                       --     --      --      --      --       8        --       9
                                                                                                                       Gold oxide                      --     --      --      --      --       --       --       21



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                                                                                                              CONSERVATION SCIENCE IN CULTURAL HERITAGE

Figure 4. (a) X-Ray diffraction patterns of the frame sample show results that indicate it consists
of gypsum; (b) the original ground layer consists of calcite and quartz and a small percentage of
zincate and halite; (c) X-Ray diffraction patterns of the reddish-brown colored sample show it is
magnetite with a small percentage of hematite; (d) the green blue color is wollastonite; (e) X-Ray
diffraction patterns of the deep green sample show it is malachite; (f) X-Ray diffraction patterns
of the light green sample show it consists of malachite with litharge; (g) X-Ray diffraction patterns
of the red color show it consists of hematite and a mixture of magnetite with zinc oxide; (h) X-Ray
diffraction patterns of the golden color sample show it consists of gold oxide.

   3.3. Scanning electron microscope coupled with EDX (SEM-EDX)

    The EDX patterns of the mural paintings from El Sakakeny Palace indicate the
following results, resumed in Figure 5-10. Observations, made by SEM, of the deterio-
rated mural painting samples, show the presence of halite crystals (the salt was identi-
fied by XRD) on the surface and in depth, as well as calcite crystals homogenously
connected to large-sized quartz crystals.


                                                                                                        131
                                                                                                                      Table 2. Results of X-ray Fluorescence analysis of six samples from paintings at El Sakakeny
                                                                                                                      Palace, confirming results of the X-Ray diffraction analysis.
K.K. Salama, M.F. Ali, A.M. Moussa - Analytical study of the materials used in mural paintings in the love chamber




                                                                                                                       Sample                                         Elements %
                                                                                                                                   Ti      P        Si        S        Ca        K      Fe      Cl      Zn     Cu
                                                                                                                          1s      0.01    0.53    17.38      1.31     39.76     0.27   1.01    0.42    0.25    0.18
                                                                                                                          2s      0.20     --      5.21     15.82      2.84     0.96   1.56    2.84    2.62    3.05
                                                                                                                          3s      0.19     --      0.51     18.34     34.68     0.67   0.46    1.16    1.12    0.21
                                                                                                                          4S      0.80     ---     2.21     14.64     28.29     3.20   0.81    5.65    5.22    0.50
                                                                                                                          5s      0.62    -----   14.50     12.16     20.26     2.07   0.75    4.46    0.56    0.42
                                                                                                                          6s      1.47    -----    1.47     20.96     25.18     0.49   0.47    2.44    2.50    0.01




                                                                                                                      Figure 5. On left Sample A taken from ground layer showing large quartz crystals which evidence
                                                                                                                      the homogeneity of the mortar and on right EDX image showing the elements, the major elements
                                                                                                                      being Ca, Si, S.




                                                                                                                      Figure 6. On left Sample B taken from reddish brown color showing the large quartz crystals,
                                                                                                                      the homogeneity of the paint layer and on right EDX image showing the elements and the major
                                                                                                                      elements being Ca, Si, S.




                                                                                                                      Figure 7. On the left Sample C taken from ground layer showing large quartz crystals connected
                                                                                                                      with gypsum which evidence the homogeneity of the mortar and on the right EDX image showing
                                                                                                                      elements in the samples, the major elements being Ca, S, Cl and Cu.


                                                                                                                132
Figure 8. On left Sample D taken from green blue color showing large crystals of color consisting
of wollastonite (after XRD analysis) and on right EDX image showing elements in the samples,
the major elements being Ca, S, Cl and Cu.




Figure 9. On left Sample E taken from deep green color showing large color crystals which
evidence the homogeneity of the paint layer and consisting of malachite and hematite and on
right EDX image showing elements in the samples, the major elements being Ca, S, Cl and Cu.




                                                                                                          CONSERVATION SCIENCE IN CULTURAL HERITAGE

Figure 10. On left Sample F taken from light green color showing large crystals of colors which
evidence the homogeneity of the paint layer and on right EDX image showing elements in the
samples, the major elements being Ca, S, Cl and Cu.


   3.4. Fourier Transform Infrared –Attenuated Total Reflectance (FTIR-ATR)

   The samples were placed inside a spectrophotometer to obtain the analyses as
spectra on graph paper, [6] OH stretching 3545.49 cm-1, asymmetric C-H stretching of
aliphatic group 2924.52 cm-1, 2853.17 cm-1, overtones 2362.37 cm-1 and C-O stretch-
ing 1140.69cm-1. Readings show that the medium used in the painting is linseed oil,
though the gold color is applied using the medium of animal glue [7].




                                                                                                    133
K.K. Salama, M.F. Ali, A.M. Moussa - Analytical study of the materials used in mural paintings in the love chamber




                                                                                                                      Figure 11. (a) The medium in the red color shows asymmetric OH stretching absorption at 3545.49
                                                                                                                      cm-1 ,OH bending at 1317 cm-1 and C-O stretching at 1140.69 cm-1: readings proved that the
                                                                                                                      binding medium used in the painting is linseed oil; (b) the medium in the wollastonite color
                                                                                                                      shows asymmetric OH stretching absorption at 3545.49 cm-1,OH bending at 1317 cm-1and C-O
                                                                                                                      stretching at 1140.69 cm-1 : readings proved that the binding medium used in the painting is
                                                                                                                      linseed oil; (c) the medium in the reddish brown color shows asymmetric OH stretching absorption
                                                                                                                      at 3545.49 cm-1, OH bending at 1317 cm-1 and C-O stretching at 1140.69 cm-1: readings proved
                                                                                                                      that the binding medium used in the painting is linseed oil; (d) the medium in the deep green
                                                                                                                      color shows asymmetric OH stretching absorption at 3545.49 cm-1, OH bending at 1317 cm-1 and
                                                                                                                      C-O stretching at 1140.69 cm-1: readings proved that the binding medium used in the painting is
                                                                                                                      linseed oil; (e) the medium in the gold color shows absorption of NH stretching at 3545.49 cm-1
                                                                                                                      and C=O stretching at 1622 cm-1: readings proved that the binding medium used in the gold color
                                                                                                                      is animal glue; (f) the medium in the ground layer shows absorption of NH stretching at 3545.49
                                                                                                                      cm-1, and C=O stretching at 1622 cm-1: readings proved that the binding medium used in the
                                                                                                                      ground layer is animal glue and OH absorption for CaSO4 · H2O is 3.404 cm-1 and SO4 bending
                                                                                                                      601 cm-1 and O-C-O for calcite 885 cm-1.



                                                                                                                         4. Conclusion

                                                                                                                          This paper presents the initial stages for restoration of three mural paintings in El
                                                                                                                      Sakakeny Palace. The study focused mainly on the physical and chemical properties
                                                                                                                      of the painting compounds and the main changes that occurred in the painting materi-
                                                                                                                      als, which caused deterioration and detachment of parts of the paintings. This allowed
                                                                                                                      us to find the best solution for their restoration.


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   Based on the analysis and testing results, below are the findings and conclusion of
the research project:
     1) The ground layer of the paintings consists of zincate with gypsum mixed to-
        gether in the ratio of 3:2.
     2) The medium used in the ground layer is animal glue.
     3) The main chemical component of the frame is only pure gypsum.
     4) The main reason for deterioration and detachment of the painting layers is the
        halite which is considered to be one of the major factors of deterioration.
     5) The colors used in the paintings are:
        – red, which is hematite;
        – yellow, which is litharge;
        – green, which is malachite;
        – black, which is magnetite;
        – blue, which is wollastonite;
        – the mixture of reddish brown consists of hematite and azurite mixed together
           in the ratio of 3:1;
        – and the light green color consists of litharge, malachite and calcite mixed
           together in the ratio of 3:2:1.
       6) All Italian artists in that period mixed their colors with linseed oil to make them
          bright and shiny, but in the golden color the medium is animal glue.


      Acknowledgements

      The authors thank the staff at El Sakakeny Palace for their help and support.




                                                                                                      CONSERVATION SCIENCE IN CULTURAL HERITAGE
      References

[1]     Novonty, F. (1960) Painting and sculpture in Europe 1780-1880, 2nd edition,
        London: Yale University Press, pp. 1-483
[2]     Lucas, A., Harris, J.R. (1962) Ancient Egyptian Materials and Industries, London:
        Dover Publications, pp. 214-220.
[3]     Henn, J. (1996) Introduction to painting and drawing, United Kingdom: Grand
        book LTD., p. 94
[4]     Arnold, A., Zehnder K.K. (1987) Monitoring Wall Painting Affected by Soluble
        Salts. In: The Conservation of Wall Painting, Proceeding of Symposium organ-
        ized By Court auld Institute of Art & Getty Conservation Institute, London, pp.
        103-115.
[5]     Ashurst, J. (1998) Conservation of building & decorative stone, plant a tree, Lon-
        don: Butterworth publications, p. 15.
[6]     Derrick, M.(1995) Infrared Spectroscopy in Conservation Science, Scientific
        Tools For Conservation, The Paul Gutty Conservation Institute, Los Angeles, p.
        198.
[7]     Stuart, B.H.(2007) Analytical techniques in materials conservation, England:
        John Wiley & Sons Ltd., pp.142-144.




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                                                                                                                        Biographical notes

                                                                                                                          Kholod Khairy Salama is a PhD candidate in the Department of Conservation of
K.K. Salama, M.F. Ali, A.M. Moussa - Analytical study of the materials used in mural paintings in the love chamber




                                                                                                                      Cultural Heritage at the Faculty of Archaeology in Cairo University and a conservator
                                                                                                                      at the Conservation Center in the National Museum of Egyptian Civilization (NEMC).

                                                                                                                         Mona Fouad Ali has a PhD in conservation and is a professor of Conservation in
                                                                                                                      the Conservation Department at the Faculty of Archaeology, Cairo University, Egypt.

                                                                                                                         Abubakr Mohamed Moussa has a PhD in conservation and is associate profes-
                                                                                                                      sor of cultural heritage conservation in the Conservation Department at the Faculty of
                                                                                                                      Archaeology, Cairo University, Egypt.




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