10.6092/issn.1973-9494/10671
The paper presents the results from Raman spectroscopy (RS) analyses of the works of Szymon Czechowicz and his workshop ‒ the most important Polish baroque painter. RS was used for clarification and supplementation of results carried out by the methods: Infrared False Colour (IRFC), XRF, XRD, SEM-EDS, GC-MS, and ATR-FTIR. A complementary analysis of the artist’s work allowed the characterisation of the fillers and the binders of the grounds and the paint layers in his art. The presented results showed that RS was especially useful for identifying the pigments used in the mixtures. It allowed the presence of Prussian blue in the blue and green colours to be determined and made it possible to distinguish the types of iron pigments in the mixtures. The method was useful also for the identification of several types of black pigments in the samples and to identify the massicot in the ground layers which contained another lead pigment – lead white. Tables and figures show the summation of test results carried out by RS analysis, the indication of specific chemical compounds in the painting layers and grounds, all of which provide additional information about the workshop of the most important painter of Polish Baroque. The main conclusion is that without using RS, it would be impossible to achieve these precise research results, helpful in the authentication of Szymon Czechowicz’s works.
application/pdf
1973-9494
10671
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Ewa Doleżyńska-Sewerniak
Conservation Science in Cultural Heritage
Raman spectroscopy
Raman Spectroscopy of the Works of Szymon Czechowicz (1689-1775)
Text.Serial.Journal
https://conservation-science.unibo.it/
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Articles
2020-03-18
2020-03-17
2020-03-18
2020-03-18
231-249
CSCH
Ewa Doleżyńska-Sewerniak
2019
10.6092/issn.1973-9494/10671
231
Faculty of History, Department of the History of 20th Century Art in Central Europe and in Emigration, Nicolaus Copernicus University in Toruń
1973-9494
Raman spectroscopy
en
249
Raman Spectroscopy of the Works of Szymon Czechowicz (1689-1775)
https://conservation-science.unibo.it/article/download/10671/10609
19
R    AMAN SPECTROSCOPY OF THE WORKS OF SZYMON
     CZECHOWICZ (1689-1775)

  Mirosław Sawczak
  Institute of Fluid-Flow Machinery, Polish Academy of Sciences, Gdansk, Poland

  Ewa Doleżyńska-Sewerniak*1
  Faculty of History, Department of the History of 20th Century Art in Central Europe
  and in Emigration, Nicolaus Copernicus University in Toruń, Poland




  Keywords: painting materials analysis, authentication, Szymon Czechowicz, Ra-
man spectroscopy


  1. Introduction

    The Polish and the Ukrainian collections of Szymon Czechowicz’s works are the
subject of this study. The artist (Figure 1) was born in Cracow in 1689 and made his
first steps in the profession at the court of Maximilian Franz Ossoliński under the super-
vision of an anonymous painter. Ossoliński perceived the talent of his pupil and sent
him to continue his studies in Rome around 1711 where he spent around twenty years.
In 1716 he took part in the prestigious Clementine competition of the Academy of Saint
Luke. He won the third prize of the second grade in the painting category for the draw-
ing entitled The victorious return from the war expedition. This enabled him to become
acquainted with the paintings of artists such as Raphael, Reni, Baraccio, Rubens, van
Dyck and others, whose pictures he copied. The best known and archivally certified
work of the artist from this period is the image of Saint Jadwiga, made for the Polish
church of Saint Stanisław in Rome. In the Eternal City, the artist also painted for other
Polish churches; among them the Piarist church in Cracow and the Assumption of the
Blessed Virgin Mary for the Cathedral in Kielce.
    Around 1731, Czechowicz returned to Poland and tried to gain the title of court
painter but was unsuccessful. In the 1750s he had a studio in a tenement house in the
Old Town in Warsaw, together with the painter Łukasz Smuglewicz (1709-1780). He
trained numerous students who, after his death, reproduced the composition schemes
and technique learned in the master’s studio. Their studio was recognized as the first
Polish school of painting. Czechowicz’s best and most well-known students included
Antoni Albertrandi, Jan Bogumił Plersch and, related to him, the famous family of art-
ists, the Smuglewicz, among them the especially outstanding Franciszek Smuglewicz.
    Czechowicz was an independent artist who worked for various church and secular
contractors. His paintings are mainly focused on religious themes, but he painted por-
traits as well. His patrons were high priests and Polish magnates such as Ossoliński,
Tarło, Sapieha, Sułkowski, Branicki and the Rzewuski family. He was commissioned to

*1 Corresponding author: ewokado@poczta.onet.pl
                                                                                              paint art works by the Piarists nationwide. He also painted for the Jesuits, the Capu-
                                                                                              chins, the Carmelites, the Visitants and others. He worked in many localities then be-
                                                                                              longing to the Polish-Lithuanian Commonwealth, located in today’s Poland, Lithuania,
                                                                                              Ukraine and Belarus: in Warsaw, Cracow, Poznań, Podhorce, Polotsk, Vilnius and
                                                                                              many others [1]. In all he left several hundreds of paintings and dozens of drawings.
M. Sawczak, E. Doleżyńska-Sewerniak - Raman spectroscopy of the works of Szymon Czechowicz




                                                                                              Figure 1. “Portrait of Szymon Czechowicz”, by an unknown 19th-century painter (The National
                                                                                              Museum in Warsaw/ Poland)



                                                                                                 This paper presents the results of Raman spectroscopy (RS) examinations of
                                                                                              dozens of the works painted by Szymon Czechowicz (1689-1775) and his work-
                                                                                              shop, the most outstanding and prolific Polish artist of the late baroque. The stud-
                                                                                              ies are part of a large project concerning the characterisation of his oeuvre, tech-
                                                                                              niques, and the technology used by Czechowicz. It also includes, conservation
                                                                                              research on the paintings that have been attributed to the artist, selected works by
                                                                                              his students and a comparative study of those paintings whose authorship is uncer-
                                                                                              tain. The importance of the artist made this research necessary, as well as the fact
                                                                                              that numerous works have been falsely attributed to him. This erroneous informa-
                                                                                              tion is popularised by websites with their extraordinary power of dissemination, of-
                                                                                              ten resulting in mistaken assessments of his artistic achievements, especially from
                                                                                              the perspective of Polish art. For these reasons, in the period from 2012 to 2017,
                                                                                              the paintings of the artist from the Polish, Lithuanian and Ukrainian collections
                                                                                              were subjected to invasive and non-invasive tests. Before the chemical analysis,
                                                                                              a series of photographs of the paintings were taken in different ranges of electro-
                                                                                              magnetic radiation: ultraviolet light, near infrared and X-radiation. An elemental,


                                                                                        232
non-destructive analysis of the paint layers was carried out using a portable X-ray
fluorescence spectrometer (XRF). Samples were also taken for specialist examina-
tions such as X-ray fluorescence spectrometry (XRF), X-ray diffraction (XRD) and
ATR infrared (FTIR) tests. In addition, an analysis of the elemental composition
was performed for the cross-section samples using Scanning Electron Microscope
coupled with an EDS electron microprobe (SEM-EDS). If any of the analyses gave
ambiguous results, RS was employed for clarification. In this paper we present the
results concerning only the pigments and the fillers of the paint and ground layers,
as these results were the most significant.


  2. Experimental

   Raman spectra were recorded using a SENTERRA Micro-Raman spectrometer
equipped with two lasers, providing excitations at 532 nm and 488nm. The confo-
cal microscope with objectives of 50x magnification assured the spectral footprint
of the sample surface area down to about 5x5 μm2. Detection was provided by a
Peltier-cooled CCD detector operating at -65 oC. The spectrometer calibration was
performed using the polystyrene standard. Spectra were acquired over a range of
50–4000 cm–1 at a resolution of 3 cm–1. Depending on the signal intensity, up to 20
spectra of individual samples (5s acquisition) were accumulated and averaged. Pig-
ments and paint components were identified based on the reference spectra from
digital Raman libraries [2, 3, 4, 5].
   Elemental analysis of paint layers was carried out using a portable X-ray fluores-
cence spectrometer (XRF) constructed in the Department of Photophysics of the Pol-
ish Academy of Sciences in Gdańsk. This spectrometer was equipped with an X-ray
excitation source operating at 55 kV (Oxford Instruments) and a sensitive SDD type
detector (Ketek) with an energy resolution of 155 eV for the Mn Kα line (5.9 keV).




                                                                                              CONSERVATION SCIENCE IN CULTURAL HERITAGE
Detection depended on the elemental atomic mass and ranged from 50 to 340 ppm.
Since the measurements were conducted in regular air atmosphere, the measurement
range was limited to elements with the atomic number Z: 19≤ Z ≤ 92. The research was
conducted on the objects in-situ in museums and churches [6-8].
   In addition, an analysis of the elemental composition was performed for the cross-
section samples using a JSM-6380LA (JEOL) Scanning Electron Microscope coupled
with an EDS electron microprobe. Energy Dispersive X-ray micro-analyses were per-
formed at the Department of Geology of the Warsaw University. The test data encom-
passed: – accelerating voltage: 20kV, – beam current: 60mA, – vacuum: 30 Pa, – dura-
tion of point analysis and the area: 100s – working distance: 10m. The research was
conducted using the so-called low vacuum technique. The pictures were recorded in
the light of reflected electrons.
   The diffraction patterns of the tested samples were made by the Structural Powder
Diffractometry Team from the Faculty of Chemistry of the Jagiellonian University. The
samples were subjected to the non-reflective bracket for diffraction measurement. The
X-ray diffraction (XRD) experiments were performed using Cu Kα radiation from a
PanalyticalX’pert pro MPD diffractometer. The measurements were taken employing
Bragg-Brentano geometry in the 2θrange of 4.0-60.0° with a measurement step size of
0.026°. Analysis of the obtained diffraction images was made in the X’pert HighScore
program, using the PDF-4 + 2014 diffraction database [9].


                                                                                        233
                                                                                                 For further pigment analysis, the ATR infrared (FTIR) technique was applied. The
                                                                                              analyses were performed respectively with the Bruker Alpha FTIR spectrometer
                                                                                              (Bruker) and IR Affinity-1 (Shimadzu), equipped with a Gladi ATR attenuated total
                                                                                              reflection (ATR) accessory with a diamond crystal (Pike Technologies). A total of 60
                                                                                              scans were collected in the 4000–400 cm-1 spectral range, while the resolution em-
                                                                                              ployed was 4 cm-1 [10-12].


                                                                                                3. Results and discussion
M. Sawczak, E. Doleżyńska-Sewerniak - Raman spectroscopy of the works of Szymon Czechowicz




                                                                                                  The RS studies were performed only for those samples for which the other tech-
                                                                                              niques. i.e. XRF, SEM-EDS, XRPD, FTIR, gave unclear results.
                                                                                                  The collection of pigments in the eighteenth century was very limited. The results
                                                                                              of the research show that Czechowicz applied only a few pigments and that they were
                                                                                              easily available. Moreover, the complex studies of the paintings proved that he nar-
                                                                                              rowed down the paint-palette used by his contemporaries to a few basic elements. In
                                                                                              the painter’s workshop, burdened with a great many orders, price certainly played a
                                                                                              considerable role in the selection of materials. These were mainly iron oxide pigments:
                                                                                              yellow, red, brown; lead pigments: lead white, massicot; black pigments: bone black,
                                                                                              lamp black, and vine black. In addition, he used pigments such as Naples yellow, cin-
                                                                                              nabar, Prussian blue as well as organic reds.
                                                                                                  The elemental analyses performed directly on the tested object with the XRF
                                                                                              method gave a general view of the composition of the studied areas or points. Fur-
                                                                                              ther specific information about the composition of individual technological layers and
                                                                                              specific pigment aggregates were obtainable thanks to the SEM-EDS assays ex-
                                                                                              ecuted on the cross-sections. An unambiguous interpretation of the results is pos-
                                                                                              sible only for some of these, i.e. those with a very characteristic composition, such
                                                                                              as cinnabar (HgS). However, these methods are unable to distinguish pigments with
                                                                                              a similar elemental composition of mixtures, such as for example iron or lead pig-
                                                                                              ments. Moreover, distinguishing all types of carbon blacks in mixtures is impossible.
                                                                                              XRD can solve some problems; the main drawback of this method being the amount
                                                                                              of the sample used for the analysis. Therefore, RS was necessary to identify the
                                                                                              types of paint and ground layer compounds.


                                                                                                3.1. Grounds

                                                                                                  Szymon Czechowicz used coloured grounds in different shades of so-called
                                                                                              salmon, red, pink and rarely, the brown colour which is sometimes observed on
                                                                                              the canvas edge of his paintings and on the reverse of canvases that have been
                                                                                              improperly sized (Figure 2). The fact that the artist used such coloured grounds
                                                                                              is not surprising, because they were the shades that were predominantly used in
                                                                                              that epoch. Reddish grounds are commonly called bolus grounds. Bolus denotes
                                                                                              a high-quality red hue clay. The bolus ground layer has an Italian pedigree and
                                                                                              were in common use in the seventeenth and eighteenth centuries [12]. As the art-
                                                                                              ist was active in Rome, the presence of this kind of ground in his works was to be
                                                                                              expected. Analysing the cross sections of the pictures and elemental composition
                                                                                              of these layers, obtained by the use of the XRF and SEM-EDS tests, in the works


                                                                                        234
correctly attributed to the artist, the research revealed principal elements such as:
C, O, Pb, Ca, Al, Si and Fe (seldom Mg, S, Mn, As and in traces K, Na). The XRD
analysis resulted in identification of the main fillers, such as chalk (Ca(CO3)), differ-
ent kinds of lead whites: cerussite (Pb(CO3)), and hydrocerussite (Pb3(CO3)2(OH)2),
silica (SiO2) and in some samples, gypsum (Ca(SO4)(H2O)2).
    The obtained results suggest that the reddish preparatory layer is mainly com-
posed of iron oxides with aluminosilicates and white grains of lead white and chalk,
sometimes gypsum. The Al, Ti, Zn, Si, Mn, K as well as the As, are the chemical
elements originating from easily accessible minerals commonly present in natural
earth pigments from iron oxide deposits. Raman spectra also confirmed the pres-
ence of bands characteristic of chalk − 283, 712 and 1083 cm-1, lead white – 1053
cm-1, as well as iron oxides (Fe2O3) − 670 cm-1. According to the data, spectral
changes such as the broadening of the bands below 290 cm-1 were also found; in
addition there were peaks near 400 cm-1 (here up to 408 cm-1) which are obvious
for materials with substituted Al in haematite (Al-doped haematite) [11]. Thus, one
can conclude that the ground layers contain a mixture of iron and alumina oxides
(Al2O3 and Fe2O3).




                                                                                                        CONSERVATION SCIENCE IN CULTURAL HERITAGE




Figure 2. A: Detail of the canvas edge of the oil painting “Saint Margaret Mary Alacoque before
Christ” (Lviv Museum of the History of Religion, Ukraine); B: fragment of the reverse of the
“Progenitor of the Ossoliński family” (The Royal Castle in Warsaw/Poland); C: cross-section
showing ground layer of the painting “Progenitor of the Ossoliński family” (The Royal Castle in
Warsaw/Poland).




                                                                                                  235
                                                                                                 Raman spectra tests, moreover, surprisingly revealed bands centred at 86, 142
                                                                                              and 282 cm-1 which are characteristic for massicot (PbO) and indicated it as one
                                                                                              of the main fillers in the layers [14], apart from another lead-based pigment ‒ lead
                                                                                              white (Figure 3). Yellow massicot, with a small amount of iron oxides (Fe2O3) tinges
                                                                                              the grounds in all the pictures from Czechowicz’s studio. Massicot can be found
                                                                                              as a natural mineral, though it is only found in small amounts. In past centuries it
                                                                                              was mined [15, 16]. Differentiating lead white and massicot by means of XRF or
                                                                                              SEM-EDS in such mixtures was not possible. The presence of massicot in ground
                                                                                              layers in that period of time was not common and unique in Polish art. For that
                                                                                              reason, the grounds used by Czechowicz are not typical bolus grounds. Massicot
M. Sawczak, E. Doleżyńska-Sewerniak - Raman spectroscopy of the works of Szymon Czechowicz




                                                                                              is the ground filler in almost all the pictures painted by the artist and is absent in
                                                                                              those which were pained by his followers and in the works incorrectly attributed to
                                                                                              him. The presence of massicot in the analysed works may therefore, at times, help
                                                                                              in determining their authorship.




                                                                                              Figure 3. Raman spectra of selected grounds in the oil on canvas paintings: (5)”Saint Barbara”
                                                                                              (Lublin/Poland; (6)”Scenes from the life of Saint Anna” (Cracow/Poland); (7)“Saint Barbara”
                                                                                              (Drzewica/Poland); (14)“Resurrection” (The National Museum in Cracow/Poland).




                                                                                        236
  3.2. Blue pigments

    In the composition of the blue pigment in Szymon Czechowicz’s paintings, in almost
all analysed samples the SEM-EDS method (Figure 4) identified a significant presence
of aluminium (Al), lead (Pb) and calcium (Ca), with a small amount of iron (Fe). This
suggested the presence of Prussian blue (Fe4 [Fe (CN)6] 3) with fillers, such as chalk
or lead white. Moreover, the large amount of Al in the samples could indicate an ad-
ditional filler, e.g. white clay.
    The RS studies proved the presence of Prussian blue based on the characteristic
bands at 2151, 532 and 270 cm-1 (see Figure 5). This blue pigment was discovered
in Berlin in 1704 by the dyer Jacob Diesbach and is known as a very strong dark
blue colourant, which is why it was commercially available as an already lightened
colour. In Czechowicz’s works, it appeared around 1730 and became the main blue
pigment in the painter’s works. In the analysed image samples, it appears in a
mixture with carbon black (the characteristic bands at 1596 and 1335 cm-1) in the
shadows of the dark blue robes, as well as with lead white (1049 cm-1) in the lighter
areas of the robes.
    XRD studies showed the presence of cerussite (Pb (CO3)), hydrocerussite
(Pb3(CO3)2(OH)2) and calcite (CaCO3) in the blue layers. The same components
were identified in the whites used by the artist by XRD which may suggest the
whitening of Prussian blue with the artist’s white paint. Both Raman studies and
XRD did not confirm the presence of white clay. Analysis of the literature on the
subject, describing the methods of obtaining Prussian blue in the eighteenth cen-
tury, informs us that Prussian blues containing a significant amount of aluminium
were produced using alum. Aluminium is a by-product of the reactions occurring in
the manufacturing process of Prussian blue and is not related to the structure of
the pigment [17, 18].




                                                                                                  CONSERVATION SCIENCE IN CULTURAL HERITAGE
  3.3. Green colour

    Studies of samples taken from the greens of both draperies and landscape ele-
ments of the analysed works revealed the presence of Fe together with Pb, Al, Ca, and
Si (Figure 6). The elements, present in low concentrations, were Mg, S, Na, Hg, K, As,
P and Sb. The artist obtained the green colour by mixing several pigments. This effect
is visible in the cross sections, suggesting the presence of green earth in the samples.
However, the RS analyses clearly show that the iron identified in the green layers origi-
nates from Prussian blue, which is very easily identified by this method (Figure 7). In
the RS analyses of the green pigments, the bands characteristic of Prussian blue ap-
peared each time: at 2153, 534 and 272 cm-1. To obtain the green colour, Czechowicz
mixed Prussian blue with yellow pigments, which were most probably composed of
Naples yellow (Pb3(SbO4)2) (135, 326, 708 cm-1), iron oxide and hydroxide compounds
such as burnt sienna (292, 408, 466, 610 cm-1), raw sienna (300, 391, 555 cm-1), yel-
low ochre, as well as bone black (1603, 1354 cm-1), lamp black (1585, 1348 cm-1), vine
black (1265, 1353, 1602 cm-1) and chalk (1084 cm-1). In some samples bone black
or lamp black were identified with yellow pigments ‒ Naples yellow and the above-
mentioned iron-based pigments.



                                                                                            237
M. Sawczak, E. Doleżyńska-Sewerniak - Raman spectroscopy of the works of Szymon Czechowicz




                                                                                              Figure 4. A: Oil on canvas ”Scenes from the life of Saint Anna” (Cracow/Poland); B: cross-section
                                                                                              showing the blue paint layer of the painting; C: Energy Dispersive X-ray microanalyses results of
                                                                                              the cross-section of the blue paint layer sample using an electron microprobe (SEM-EDS).




                                                                                              Figure 5. The Raman spectra of selected blue paint layer samples confirming the presence of
                                                                                              Prussian blue (Fe4[Fe(CN)6]3): (20)“Way of the Cross” (Lviv Museum of the History of Religion,
                                                                                              Ukraine); (5) ”Saint Barbara” (Lublin/ Poland); (25)”Saint Joseph” (The National Museum in
                                                                                              Warsaw/Poland).



                                                                                        238
Figure 6. “Saint Elisabeth” (Tykocin/Poland), fragment. A: photo in visible light; B: and in macro-
XRF with the iron (Fe) distribution map. A green fragment is marked by a yellow rectangle




                                                                                                            CONSERVATION SCIENCE IN CULTURAL HERITAGE




Figure 7. Raman spectra of selected green paint layers, samples: (19)”Saint Benedict” (Lviv
Museum of the History of Religion, Ukraine); (9)”Annunciation of the Virgin Mary” (Lubartów/
Poland); (27)”Christ Giving the Keys to St. Peter” (The National Museum in Warsaw branch in
Łowicz, Poland).




                                                                                                      239
                                                                                                 3.4. Iron pigments

                                                                                                 The results of the study of the paint layers in Szymon Czechowicz’s works show
                                                                                              that the natural iron pigments are the basic ones used by the artist (Figure 8). The
                                                                                              results from the SEM-EDS and XRF studies of the brown and yellow layers very often
                                                                                              reveal the presence of iron (Fe) with elements such as: Mg, As, Ti, Al, Si, Ba, Mn, Zn,
                                                                                              which are present in the accompanying minerals commonly found in natural pigments
                                                                                              with an iron oxide or hydroxide base. The iron compounds were identified in the layers
                                                                                              of yellow, where different forms of FexOy with a different degree of hydration, are also
                                                                                              very common. Yellow ochre (FeO(OH)·nH2O) was mixed by the artist with white lead,
M. Sawczak, E. Doleżyńska-Sewerniak - Raman spectroscopy of the works of Szymon Czechowicz




                                                                                              as well as Naples yellow (Pb3(SbO4)2). Chalk was also identified in the yellow layers, as
                                                                                              well as silica. In the picture Scenes from the life of St. Anna (Cracow), limonit (2Fe2O3
                                                                                              • nH2O) was identified, as well as warm ochre. In the yellow samples taken from the
                                                                                              paintings in the Church of the Holy Trinity in Tykocin, arsenic (As) was identified by
                                                                                              the use of SEM-EDS tests, while in the pictures painted in Lwów, magnesium (Mg)
                                                                                              and titanium (Ti) were identified in the yellow layers, indicating the different sources of
                                                                                              natural yellow pigments used by the artist.
                                                                                                 As mentioned above, iron pigments were recognized also in the greens (mentioned
                                                                                              above, burnt and raw sienna, yellow ochre) and in the grounds (mentioned above,
                                                                                              Fe2O3). All shades of brown, both dark and bright, were obtained by the artist using a
                                                                                              mixture of iron pigments with cinnabar (HgS), lead white, chalk, Naples yellow, carbon
                                                                                              black (C), bone black (Ca3(PO4)2 + CaCO3 + C) and sometimes Prussian blue. The
                                                                                              precise assessment of the type of iron pigment in the brown layers was possible only
                                                                                              through the RS analysis (Figure 9) [19]. The brown layers revealed the presence of
                                                                                              characteristic bands of mainly burnt (292, 408, 466, 610 cm-1) and raw sienna (300,
                                                                                              391, 555 cm-1), as well as warm ochre (608, 408, 293, 226 cm-1). Burnt sienna domi-
                                                                                              nated in the browns of Czechowicz’s pictures. The artist mixed it with cinnabar and
                                                                                              lead white with chalk. In order to obtain darker shades of brown, he mixed it with black
                                                                                              pigments, mainly bone and lamp black. Using non-invasive XRF tests for the brown
                                                                                              colour of the paintings from the Church of the Holy Trinity in Tykocin, in addition to iron
                                                                                              (Fe), manganese (Mn) was identified, suggesting the presence of raw umber.


                                                                                                 3.5. Black pigments

                                                                                                 The most popular black pigments in the eighteenth century were bone and ivory
                                                                                              black and had been known since ancient times. They generally contained calcium
                                                                                              phosphate (Ca3(PO4)2, calcium carbonate (CaCO3) and carbon (C); vine black con-
                                                                                              tained 90% carbon (C), insoluble carbon compounds and ashes and lamp black which
                                                                                              is an amorphous carbon black made from condensed smoke from the burning of min-
                                                                                              eral oil, tar, pitch or resin. For the identification of the black pigments, point analyses
                                                                                              were used on cross-sections using the SEM-EDS method. The black points of vari-
                                                                                              ous painting layers were analysed, because black in its pure form does not occur in
                                                                                              the artist’s works. Very often carbon (C) and phosphorus (P) were identified in these
                                                                                              analyses. This clearly indicates that bone black was used in the painter’s works. It was
                                                                                              also confirmed by Raman tests which revealed characteristic bands for this pigment,
                                                                                              centred near 1603 and 1354 cm-1. In a large group of images, SEM-EDS also identified
                                                                                              pure carbon (C) on selected dark points.


                                                                                        240
Figure 8. “Saint Szczepan” (Tykocin, Poland). Fragment – A: photo in visible light; B: macro-XRF
with iron (Fe) distribution map.




                                                                                                         CONSERVATION SCIENCE IN CULTURAL HERITAGE




Figure 9. Raman spectra of selected paint layers containing iron oxide pigments: (27)”Christ
Giving the Keys to St. Peter”(The National Museum in Warsaw branch in Łowicz, Poland);
(6)”Scenes from the life of Saint Anna” (Cracow/Poland); (7)”Saint Barbara” (Drzewica/Poland);
(3)”Progenitor of the Ossoliński family” (The Royal Castle in Warsaw, Poland).




                                                                                                   241
                                                                                                  RS is known as a very sensitive method for analysing carbonaceous materials;
                                                                                              especially the ID/IG ratio which is mainly applied to differentiate the various kinds of
                                                                                              carbons [20, 21]. A D band is forbidden in graphite structures and its appearance in
                                                                                              Raman spectra is connected with double resonance Raman processes induced by
                                                                                              lattice disorder and defects causing in-plane breathing vibrations of the aromatic ring
                                                                                              structures (A1g symmetry) while the G band is assigned to the in-plane stretching vi-
                                                                                              bration of sp2 carbon (E2g symmetry). The changes in the D/G intensity ratio are not
                                                                                              only related to graphitisation of the carbon structure but also to the pyrolysis process
                                                                                              occurring during preparation of the carbon material from different organic materials
                                                                                              [22]. According to the above, by using the RS results it is possible to distinguish
M. Sawczak, E. Doleżyńska-Sewerniak - Raman spectroscopy of the works of Szymon Czechowicz




                                                                                              between carbon pigments prepared by means of different methods. However, pre-
                                                                                              cise identification of the origin of carbon pigments requires the study of documented
                                                                                              historical sources. The mixture of different carbon pigments characterised by the
                                                                                              different ID/IG ratio, even in one single sample allows us to conclude that the artist
                                                                                              used a mixture of carbon blacks of different origin to obtain the black pigment for his
                                                                                              paintings (Figure 10).




                                                                                              Figure 10. The Raman spectra of selected black pigments: (16)”Saint Bonaventure” (Węgró, /
                                                                                              Poland); (5)”Saint Barbara” (Lublin, Poland).



                                                                                        242
      4. Conclusions

   The comprehensive study of Szymon Czechowicz’s paintings presented in this work
allowed the characterization of the materials used in his studio. The results from the
RS analyses played a key role in this identification and made it possible to precisely
identify the composition of the grounds. In particular, this applies to the indication of the
presence of a massicot together with lead white used in the layers. These studies also
formed a meaningful contribution to the identification of other pigments with a similar
elemental composition that appeared in mixtures such as those in the iron pigments:
yellow, red ochre and sienna. The results from RS confirmed the presence of Prussian
blue in the layers of blue and green pigments in the analysed images.
   Interestingly, the RS research on the black pigments proved that the artist used dif-
ferent carbon mixtures to obtain black paint. Such a diagnosis is impossible to achieve
with other methods. In addition, the RS analysis confirmed the presence of pigments
used by the artist, that had already been identified by means of other methods.
   The main conclusion from the results presented here, is that without RS tests it
would be impossible to achieve such precise research results, which are helpful in the
authentication of Szymon Czechowicz’s works (see Table 1).

Table 1. The Raman tests of grounds, blues, greens, iron pigments – browns and yellows and
blacks in the works of Szymon Czechowicz and his workshop
 Nr            Title          Year    Grounds       Blues     Greens       Iron pigments        Blacks
                                                                        Browns      Yellows
 1     Saint Jadwiga          1725     massicot,      –         –        burnt         –          –
       (Rome/Italy)                   lead white                        sienna
 2     The copper snake       1714-   read lead,      –         –          –           –          –
       (Lviv Historical       1730     red ochre
       Museum)




                                                                                                               CONSERVATION SCIENCE IN CULTURAL HERITAGE
 3     The Immaculate         1730s   massicot     Prussian carbon      burnt       yellow      carbon
       Conception (Warsaw/     (?)                   blue    black,     umber     ochre, lead    black
       Poland)                                             Prussian                 white
                                                          blue, burnt
                                                            umber,
                                                             chalk
 4     Progenitor of the      1731-    massicot Prussian Prussian       burnt          –        carbon
       Ossoliński family      1734                 blue      blue,      umber                    black
       (The Royal Castle in                               chalk, lead
       Warsaw/Poland)                                        white,
                                                             burnt
                                                            umber,
                                                            carbon
                                                             black
 5     Paintings from the     1736     massicot, Prussian Prussian      burnt          –        carbon
       Missionary Church              chalk, lead  blue,     blue,      umber                    black
       (Lublin/Poland)                  white      lead      chalk,
                                                  white,     burnt
                                                  carbon    umber,
                                                   black    carbon
                                                             black




                                                                                                         243
                                                                                              6   Portrait of the         1739    massicot    Prussian       –           –           –         carbon
                                                                                                  Pomeranian voivode                            blue,                                           black
                                                                                                  Jakub Narzymski                               lead
                                                                                                  (The Kórnik Library of                       white,
                                                                                                  the Polish Academy                            coal
                                                                                                  of Sciences /Poland)                         black
                                                                                              7   Saint Francis (Lviv    around   massicot,       –          –         raw and       –           –
                                                                                                  Museum of the           1740        raw                                burnt
                                                                                                  History of Religion/              sienna,                             umber
                                                                                                  Ukraine)                        red ochre,
                                                                                                                                    minium
M. Sawczak, E. Doleżyńska-Sewerniak - Raman spectroscopy of the works of Szymon Czechowicz




                                                                                              8   Annunciation of        1740     massicot, Prussian      Prussian     burnt         –           –
                                                                                                  the Virgin Mary                 coal black  blue          blue,      umber
                                                                                                  (Lubartów/Poland)                                         chalk,
                                                                                                                                                            burnt
                                                                                                                                                           umber
                                                                                              9   Martyrdom of Saint     1740s    massicot    Prussian    Prussian     burnt         –         carbon
                                                                                                  John of Nepomuk                               blue        blue,      umber                    black
                                                                                                  (The National                                             chalk,
                                                                                                  Museum in Warsaw/                                         burnt
                                                                                                  Poland)                                                  umber,
                                                                                                                                                           carbon
                                                                                                                                                            black
                                                                                              10 Martyrdom of Saint      1740s    massicot    Prussian    Prussian      burnt        –         carbon
                                                                                                 Florian (The National                          blue     blue, lead    sienna                   black
                                                                                                 Museum in Warsaw/                                          white,
                                                                                                 Poland)                                                    burnt
                                                                                                                                                           sienna,
                                                                                                                                                           carbon
                                                                                                                                                            black
                                                                                              11 Scenes from the         1741     chalk, lead Prussian    Prussian      burnt      yellow      carbon
                                                                                                 life of Saint Anna               white, red    blue        blue,      sienna,     ochre,       black
                                                                                                 (Cracow/Poland)                    ochre                chalk, lead    warm     lead white,
                                                                                                                                                            white,     ochre,       chalk.
                                                                                                                                                            burnt       burnt
                                                                                                                                                           umber,      umber
                                                                                                                                                           carbon
                                                                                                                                                            black
                                                                                              12 Paintings from the      1745     massicot    Prussian    Prussian      burnt        –         carbon
                                                                                                 Piarist Church (Opole                          blue     blue, burnt   sienna                  black,
                                                                                                 Lubelskie/Poland)                                         umber                                silica
                                                                                              13 Way of the Cross        1747         –       Prussian        –         burnt        –         carbon
                                                                                                 (Lviv Museum of the                            blue,                  sienna                   black
                                                                                                 History of Religion/                           lead
                                                                                                 Ukraine)                                      white,
                                                                                                                                               chalk,
                                                                                                                                                coal
                                                                                                                                               black
                                                                                              14 The Entombment          1747      red lead       –          –           –           –           –
                                                                                                 (The National
                                                                                                 Museum in Cracow/
                                                                                                 Poland)




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15 Paintings from the      1749-     massicot     Prussian   Prussian       –          yellow    carbon
   Church of the Holy      1750                     blue       blue,                   ochre,     black
   Trinity (Tykocin/                                          chalk,                    chalk,
   Polnd)                                                     yellow                  cinnabar
                                                              ochre,
                                                              carbon
                                                               black
16 Christ Giving the       around    massicot     Prussian   Prussian      burnt         –         –
   Keys to St. Peter        1750                    blue       blue       sienna,
   (The National                                                        lead white,
   Museum in Warsaw                                                        chalk,
   branch in Łowicz/                                                       warm
   Poland)                                                                 ochre
17 Child Jesus (Lviv       around    massicot,     ultra-       –            –           –       carbon
   Art Gallery named        1750        raw       marine,                                         black
   after Boris Woźnicki/              umber,      Prussian
   Ukraine)                            chalk,       blue
                                     read lead
18 Child Jesus (Lviv       around      chalk,     Prussian      –         burnt          –       carbon
   Art Gallery named        1750       burnt        blue,                sienna,                  black
   after Boris Woźnicki               sienna,      caput                chalk, raw
   branch in Olesko/                 massicot     mortum                  umber
   Ukraine)
19 Saint Margaret Mary     second    massicot,    PrussianPrussian        burnt          –       carbon
   Alacoque before           half       raw         blue    blue,         umber                   black
   Christ (Lviv Museum      of the    sienna,             gypsum,
   of the History of        1750s    red lead            chalk, lead
   Religion/Ukraine)                                        white,
                                                            burnt
                                                           umber,
                                                           carbon
                                                            black




                                                                                                                CONSERVATION SCIENCE IN CULTURAL HERITAGE
20 Saint Benedict (Lviv    1756-        read    Prussian Prussian         burnt          –       carbon
   Museum of the           1758       lead, raw   blue   blue, burnt     umber,                   black
   History of Religion/              umber, red            umber,       cinnabar,
   Ukraine)                             ochre              carbon        carbon
                                                            black         black,
                                                                          chalk,
21 Saint Scholastica       1756-         –        Prussian      –           –            –         –
   (Lviv Museum of the     1758                     blue
   History of Religion/
   Ukraine)
22 The Presentation        1756-     red lead,    Prussian      –           –            –         –
   of the Virgin at        1758      chalk, red     blue
   the Temple (Lviv                    ochre
   Museum of the
   History of Religion/
   Ukraine)
23 Resurrection (The        1758     massicot     Prussian      –           –            –         –
   National Museum in                               blue
   Cracow/Poland)
24 Resurrection (Lviv       1758     massicot,    Prussian      –           –            –         –
   Art Gallery named                 chalk, red     blue
   after Boris Woźnicki                ochre
   branch in Olesko/
   Ukraine)


                                                                                                          245
                                                                                               25 Communion of Saint      the     chalk, lead Prussian    –       cinnabar,      yellow     carbon
                                                                                                  Stanislaus Kostka      end of     white,      blue               carbon        ochre,      black
                                                                                                  (Lviv Historical       1750s     gypsum,                          black,    lead white,
                                                                                                  Museum)                            raw                            chalk      chalk, raw
                                                                                                                                    umber,                                    sienna, raw
                                                                                                                                  massicot?                                      umber
                                                                                               26 Saint Barbara          1760s    chalk, lead     –       –         burnt        yellow     carbon
                                                                                                  (Drzewica/Poland)       (?)     white, red                      and raw     ochre, lead    black
                                                                                                                                    ochre                          sienna,       white
                                                                                                                                                                  cinnabar
                                                                                               27 Madonna (Lviv          around    massicot,    –         –           –           –           –
M. Sawczak, E. Doleżyńska-Sewerniak - Raman spectroscopy of the works of Szymon Czechowicz




                                                                                                  Museum of the          1760s    lead white,
                                                                                                  History of Religion/              carbon
                                                                                                  Ukraine)                           black
                                                                                               28 Saint. Bonaventure     1760s     massicot Prussian   Prussian     burnt      yellow       carbon
                                                                                                  (Węgrów/Poland)                             blue       blue,     umber,   ochre, lead      black
                                                                                                                                                         chalk,   cinnabar,    white
                                                                                                                                                         burnt     carbon
                                                                                                                                                        umber,      black
                                                                                                                                                        carbon
                                                                                                                                                         black
                                                                                               29 Saint Joseph (The      1760s    massicot   Prussian Prussian raw umber,      yellow       carbon
                                                                                                  National Museum in      (?)                  blue,  blue, burnt   burnt      ochre,        black
                                                                                                  Warsaw/Poland)                               lead     umber       umber   lead white,
                                                                                                                                              white,                         chalk, raw
                                                                                                                                              chalk                         sienna, raw
                                                                                                                                                                               umber



                                                                                                    Acknowledgements

                                                                                                 This work was supported by a grant financed by the National Science Centre in
                                                                                              Poland under Decision DEC-2013/11/B/HS2/02585. A special thank goes to Marek
                                                                                              Wisniewski for carrying RS analyses, Anna Klisińska-Kopacz and Rafał Jendrzejewski
                                                                                              for the XRF analysis, to Alicja Rafalska for the XRD research, to Jakub Kotowski for
                                                                                              the SEM-EDS tests, Kamilla Małek for FTIR and four samples of RS analyses, as well
                                                                                              as Mark Hoogslag for proofreading the final manuscript.


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                                                                                                Biographical notes

                                                                                                  Mirosław Sawczak is an associate professor in the Centre for Plasma and Laser
                                                                                              Engineering of the IFFM Polish Academy of Sciences in Gdańsk. In 2003 he defended
                                                                                              his doctoral thesis devoted to the diagnosis and shaping of parameters of high-power
                                                                                              technological CO2 lasers. Since then, he has been dealing with issues related to non-
                                                                                              destructive materials testing, using laser spectroscopy as well as X-ray fluorescence
                                                                                              techniques. He has extensive experience in the design and construction of laser based
                                                                                              and X-ray research equipment. For many years he has conducted research on the ap-
                                                                                              plication of non-destructive analytical techniques in the study of historical objects as
M. Sawczak, E. Doleżyńska-Sewerniak - Raman spectroscopy of the works of Szymon Czechowicz




                                                                                              well as in the application of lasers in cultural heritage conservation. His more recent
                                                                                              research is devoted to spintronics, nanomaterials and functional materials in the ap-
                                                                                              plication of sensors.

                                                                                                 Ewa Doleżyńska-Sewerniak obtained her Ph.D. in 2007, in the field of art sci-
                                                                                              ences. A restorer, she specializes in the study of art materials and techniques as well
                                                                                              as in the examination of the colour of historic buildings. She is a lecturer at Nicolaus
                                                                                              Copernicus University in Toruń in Poland at the Department of the History of Art and
                                                                                              Culture. In the years 2016-2019 she was an appraiser/expert of the Polish Minister of
                                                                                              Culture in the field of colour of the architecture of north-eastern Poland as well as the
                                                                                              art materials and techniques of Polish painting masters.


                                                                                                  Summary
                                                                                                  The paper presents the results from Raman spectroscopy (RS) analyses of the
                                                                                              works of Szymon Czechowicz and his workshop ‒ the most important Polish baroque
                                                                                              painter. RS was used for clarification and supplementation of results carried out by
                                                                                              the methods: Infrared False Colour (IRFC), XRF, XRD, SEM-EDS, GC-MS, and ATR-
                                                                                              FTIR. A complementary analysis of the artist’s work allowed the characterisation of
                                                                                              the fillers and the binders of the grounds and the paint layers in his art. The presented
                                                                                              results showed that RS was especially useful for identifying the pigments used in the
                                                                                              mixtures. It allowed the presence of Prussian blue in the blue and green colours to
                                                                                              be determined and made it possible to distinguish the types of iron pigments in the
                                                                                              mixtures. The method was useful also for the identification of several types of black
                                                                                              pigments in the samples and to identify the massicot in the ground layers which con-
                                                                                              tained another lead pigment – lead white. Tables and figures show the summation of
                                                                                              test results carried out by RS analysis, the indication of specific chemical compounds
                                                                                              in the painting layers and grounds, all of which provide additional information about the
                                                                                              workshop of the most important painter of Polish Baroque. The main conclusion is that
                                                                                              without using RS, it would be impossible to achieve these precise research results,
                                                                                              helpful in the authentication of Szymon Czechowicz’s works.


                                                                                                 Riassunto
                                                                                                 Il lavoro presenta i risultati delle analisi in Spettrometria Raman (RS) dei lavori di
                                                                                              Szymon Czechowicz – il più importante pittore barocco polacco – e del suo labora-
                                                                                              torio. La RS è stata usata per chiarire e completare i risultati ottenuti con le seguenti
                                                                                              tecniche: fotografia ad infrarosso a falso colore (IRFC), XRF, XRD, SEM-EDS, GC-


                                                                                        248
MS e ATR-FTIR. Una ulteriore analisi ha permesso la caratterizzazione delle cariche
e dei leganti dell’imprimitura e degli strati di colore. La presentazione dei risultati ha
mostrato che RS è stato particolarmente utile per identificare i diversi pigmenti usati
nelle miscele. È stato identificato il blu di Prussia nei colori blu e verde distinguendo
le diverse tipologie di pigmenti a base di ferro nelle miscele. Il metodo è stato anche
utile per identificare i vari pigmenti di colore nero nei campioni e il massicot (monossido
diossido) negli strati preparatori che contengono un altro pigmento a base di piombo
– biacca di piombo (carbonato basico di piombo). Le tabelle e le figure mostrano i
risultati ottenuti con il RS, i composti chimici negli strati di pittura e nell’imprimitura,
fornendo dati sulla bottega del più importante pittore barocco polacco. La conclusione
è che senza l’impiego della RS non sarebbe stato possibile ottenere i suddetti risultati,
permettendo l’autenticazione delle opere di Szymon Czechowicz.




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                                                                                               249
