10.6092/issn.1973-9494/7941
This article concerns a 19th century dispute about twenty pieces of decorated furniture painted by the 19th century painter Anders Erik Ädel (1809-1888) from Söderhamn, Hälsingland, Sweden. Ädel is considered to be one of the foremost painters in Hälsingland. His art works - painted furniture and interiors - are displayed in museums and can also be found in the Decorated Farmhouses of Hälsingland, UNESCO World Heritage. In 1839, Ädel accused his client, the farmer Erik Olofsson, in court of having paid too little for the objects he had painted as he had used more pigments than those for which he had been paid. Almost 180 years later scientific methods combined with historic source research were used to understand what pigments Ädel actually used. Through this study we demonstrate how multidisciplinary collaboration between sciences and humanities can contribute to deeper knowledge and new interpretations. The scientific analyses were preceded by analyses of the judicial protocols found. Non-invasive analyses using XRF instruments were conducted in situ, supplemented by other spectroscopic methods in the lab. The judicial protocols give an insight into what pigments Ädel had access to, and when combined with the scientific analyses, this information provides historic evidence of the artist's materials and painting technique.
application/pdf
1973-9494
7941
en
Kaj Thuresson
Conservation Science in Cultural Heritage
pigment
Forensic Art History: the Ädel Painting Dispute 1839-1841
Text.Serial.Journal
https://conservation-science.unibo.it/
17
Articles
2018-03-28
2018-03-26
2018-03-28
2019-09-06
87-99
CSCH
Kaj Thuresson
2017
10.6092/issn.1973-9494/7941
87
The Swedish National Heritage Board (RAÄ), Conservation science department, Visby
1973-9494
pigment
en
99
Lyckman Gevert, K. (2016). Målarmästarens längtan. Byggnadskultur 1:16, pp. 12-17.
Forensic Art History: the Ädel Painting Dispute 1839-1841
https://conservation-science.unibo.it/article/download/7941/7657
17
F   ORENSIC ART HISTORY: THE ÄDEL PAINTING DISPUTE
    1839-1841

   Ingalill Nyström*, Jacob Thomas, Yvonne Fors, Liv Friis7
   University of Gothenburg, Department of Conservation, Faculty of Science
   Gothenburg, Sweden

   Anders Assis
   Ljusdalsbygdens museum
   Ljusdal, Sweden

   Kaj Thuresson
   The Swedish National Heritage Board (RAÄ), Conservation science department
   Visby, Sweden

   Keywords: XRF, DSA-ToF-MS, Raman, FT-IR, folk art, pigment


   1. Introduction

   The overall purpose of this article is to show how cross-disciplinary collaboration
can contribute to new knowledge and new interpretations of written sources and histor-
ic objects. Our team consists of researchers with expertise in the broad conservation
ieldμ conservation scientists, conservators, art historians and ethnologists. Together
we have gone through the sources relating to the legal case and performed qualitative
analyses of the paint - pigments, lakes and binders - of three pieces of furniture - a




                                                                                                      CONSERVATION SCIENCE IN CULTURAL HERITAGE
table, a chest and a casket - related to the case (Figure 1).




Figure 1. Three of the pieces of furniture that Anders Erik Ädel decorated for his client Erik
Olofsson, 1839. The large chest has a secondary varnish and some other later additions such as
the external red strip at the bottom. Photograph: Anders Assis.


* Corresponding author: Ingalill.nystrom@conservation.gu.se

                                                                                                 87
                                                                                                                             The historic sources contain, in addition to judicial protocols, receipts of purchased
                                                                                                                          pigments and written comments on the artist’s materials used for the commission. Key
                                                                                                                          research questions areμ How can court documents and scientiic analyses contribute to
                                                                                                                          the understanding of a 180-year-old court case, and how can this research contribute
                                                                                                                          to the understanding of folk painters’ crafts, choice of materials, processes and skills
I. Nyström, J. Thomas, Y. Fors, L. Friis, A. Assis, K. Thuresson - Forensic art history: the Ädel painting dispute




                                                                                                                          as well as the economy of the region in the 19th century?


                                                                                                                             2. The dispute and the judicial protocol

                                                                                                                              The dispute between painter Anders Erik Ädel and his client, farmer Erik Olofsson
                                                                                                                          ran from the autumn ‘ting’ (district court assembly) in December 1839, to the spring dis-
                                                                                                                          trict court assembly in March 1841. The two parties met before the district court on four
                                                                                                                          different occasions over the course of 15 months. It began with Ädel taking legal action
                                                                                                                          against Olofsson when he claimed the client paid too little for the painting of ca. 30
                                                                                                                          pieces of furniture. Central to the case is the interpretation of the terms of the contract,
                                                                                                                          that is, whether Olofsson should have paid for the ‘time and materials used’ or only a
                                                                                                                          pre-agreed fee. Through presentations and testimonies, details of the circumstances
                                                                                                                          were clariiedμ who had paid for the purchased artist’s materials; independent valua-
                                                                                                                          tion of the work and the conditions for Ädel to undertake the commission. An expert
                                                                                                                          witness, the painter Blombertsson, was also called to give a statement. This witness
                                                                                                                          stated that Ädel must have used more pigments than those reported by Olofsson in the
                                                                                                                          receipts. Ädel did partly win the dispute, but the parties were to bear their own court
                                                                                                                          costs. Ädel had the opportunity to appeal to a higher court, which he intended to do,
                                                                                                                          but a settlement was reached before the case came up.
                                                                                                                              The circumstances and origin as well as the settlement of the litigation between
                                                                                                                          Ädel and Olofsson are not clear, but court records show that Ädel had earlier been
                                                                                                                          sued by the pigment merchant Forsberg for an unpaid bill. It might have been Ädel’s
                                                                                                                          sudden need of cash, resulting from this dispute with Forsberg, which made Ädel press
                                                                                                                          for increased payment for work rendered to Olofsson.


                                                                                                                             3. Experimental

                                                                                                                             The three objects from the legal dispute identiied according to provenance - a
                                                                                                                          chest, a casket and a table - were analysed using UV luorescence imaging, XRF, FT-
                                                                                                                          Raman, FT-IR, and DSA-ToF-MS. GC-MS will be used to add information about bind-
                                                                                                                          ing media. The XRF analysis was performed in situ at Ljusdal Bygdens Museum. UV
                                                                                                                          light examination (also in situ) was performed to be able to distinguish later additions
                                                                                                                          from original paint layers and deine regions of interest (ROI) for further examination.
                                                                                                                          XRF analyses were performed on the identiied ROI. εicro-sampling was then per-
                                                                                                                          formed for supplemental laboratory analyses. The samples were divided into aliquots
                                                                                                                          for various analyses to identify both binders and pigments. The pigment analyses were
                                                                                                                          performed at the Department of Conservation, University of Gothenburg and the bind-
                                                                                                                          er analyses with ATR FT-IR at the Archaeological Research laboratory, Department of
                                                                                                                          Archaeology and Classical studies, Stockholm University.
                                                                                                                             Artax 800 µXRF spectrometer (Bruker) equipped with Mo X-ray tube, polycapillary
                                                                                                                          lens and silicon drift detector was used for elemental analyses of pigments. Analyses


                                                                                                                     88
were performed as single point analysis (spot size <100 µm) as well as XRF mapping,
at a voltage of 50 keV, with a current of 600 µA. Measurements were carried out in situ
at the Ljusdal museum. Each individual colour of paint was measured in several posi-
tions (front, side, topside or inside depending on object) on each of the three objects re-
sulting in 40 to 90 individual analysis spots on each object. During XRF mapping, scan
time per point was 10 s and the total number of points investigated was more than 150.
    MultiRAM FT-Raman spectrometer (Bruker) equipped with a 1064 nm Nd: YAG
laser was used on the historic samples to identify pigment and lake mixtures in the
paint. The spectral resolution was 3 cm-1. The laser power and number of scans varied
depending on the pigment type. The brownish red and yellow samples which might
contain iron were exposed at a laser power of 2-6 mW for 5000-20000 scans, while
the other samples - blue, green, orange red, black and white - were exposed at a laser
power of 10-30 mW for 5000-20000 scans. To attain a representative spectrum of each
sample, 6-8 spectra were taken on 3-4 different points of the sample.
    AxION 2 Time of Flight Mass Spectrometer (Perkin Elmer) equipped with a ield-
free, APCI-like direct sample analysis (DSA) source was used to collect positive mode
high resolution mass spectra of the samples suspected of containing indigo. Samples
were analysed without extraction or chromatographic separation, with ca. 30 seconds
or less needed to collect spectra to identify the primary constituents of the analyte. The
Axion DSA conditions are as followsμ corona current of 4 A, heater 250 °C, auxiliary
gas (N2) pressure of 80 psi, drying gas (N2) low of 3 δ/min, and drying gas (N2) tem-
perature of 25 °C.
    The AxION 2 TOF εS was run in positive ionization mode with a light tube volt-
age of -8000 V. The endplate offset was set to -200 V, the capillary entrance was set
to -800 V, the capillary exit was set to 120 V for normal MS analysis. Mass spectra
were acquired with a range of 100-2000 Da with an acquisition rate of 5 spectra/sec.
To maintain mass accuracy, two lock mass ions were used (m/z 121.0514 and m/z
622.0295). All samples were analysed for 30 seconds, and the average mass spectra




                                                                                                   CONSERVATION SCIENCE IN CULTURAL HERITAGE
were calculated during post processing.
    NICOδET iS 10 Fourier Transform Infrared Spectrometer (Thermo Scientiic)
equipped with SMART iTR. A small fragment of the sample was placed directly on the
ATR crystal for analysis, which takes about two minutes. The analyses of the samples,
when compared with relevant standards, provide an indication of the remaining prod-
ucts of the original binder applied by the artist.


   4. Analytical results

    The UV-light examination showed that the chest had a secondary varnish and was
heavily retouched and repainted. The results from the pigment analyses on all three
objects are presented below and followed by the preliminary analyses of the binders.
    Blue: The XRF analyses show that the bottom layer of blue paint on all three objects
contains lead, with low concentration of calcium and iron. In the Raman spectrum, we
can see that the blue pigment is Prussian blue and in some cases Prussian blue mixed
with indigo, usually mixed with lead white and chalk (Figure 2). The indigotin peaks
are reduced and slightly shifted in the Raman spectrum probably due to deterioration
(Figure 3) [1]. DSA-ToF-MS can be used to verify the presence of indigoids. However,
in this case the binding media and all the other mixed pigments disturbed the analy-


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                                                                                                                          ses. Indigo is not mentioned in the legal protocols but is mentioned in the merchant
                                                                                                                          Forsberg’s bankruptcy documents from 1840 (FIII:1 konkursakter 1840:nr 11). In the
                                                                                                                          blue colour of the chest we can see a large amount of indigo. The casket contains a
                                                                                                                          small amount of indigo and the table contains only Prussian blue. DSA-ToF-MS did not
                                                                                                                          detect any ions with m/z 263 in any of the samples; it is possible that degradation of the
I. Nyström, J. Thomas, Y. Fors, L. Friis, A. Assis, K. Thuresson - Forensic art history: the Ädel painting dispute




                                                                                                                          indigo reduced the concentration to below the limit of detection of the technique which
                                                                                                                          has not yet been optimised.
                                                                                                                              Green: According to XRF analyses, the green colour contains copper, arsenic, lead
                                                                                                                          and a small amount of iron in different ratios between samples indicating a mixed
                                                                                                                          green. This is supported by Raman spectra which indicate malachite and emerald
                                                                                                                          green as well as Prussian blue, massicot, lead white and chalk (Figure 4). Due to the
                                                                                                                          high absorbance of the green pigments it was necessary to average many low intensity
                                                                                                                          scans to generate a usable spectrum.
                                                                                                                              Möngel: Among the painting materials mentioned in the protocols is a pigment
                                                                                                                          called “möngel”. This pigment is also called Mengel or Mängel and is litharge, ac-
                                                                                                                          cording to Tronner et al. [2-4]. Litharge (silverglitt) is mentioned in the legal protocols.
                                                                                                                          Litharge is naturally present in mixed form with different lead oxides giving differences
                                                                                                                          in colour and hue [5]. Depending on the colour, litharge in Swedish can be called sil-
                                                                                                                          verglitt (silver shine) and guldglitt (gold shine). The less colourful, silverglitt is usually
                                                                                                                          used as a siccative in linseed oil paint [6, 7]. Möngel in this case could refer to a more
                                                                                                                          colourful litharge variant and thus be a synonym for guldglitt which is not mentioned in
                                                                                                                          the protocols.
                                                                                                                              Yellow: XRF indicates iron and lead in various ratios in the yellow ROI. Yellow ochre
                                                                                                                          is dificult to detect with a 1064 nm laser line, thus with FT-Raman we can only detect a
                                                                                                                          mixture of litharge/massicot. We conclude, however, that it is a mixed yellow containing
                                                                                                                          both litharge/massicot and yellow ochre, due to elemental analysis which shows the
                                                                                                                          high content of iron. The legal protocols also disclose that yellow ochre has been used.
                                                                                                                              Red: The red painted ROI can either be an orange-red or a brown-red. The orange-
                                                                                                                          red contains mainly lead, mercury and iron, and a smaller amount of calcium. Raman
                                                                                                                          spectra show red lead, cinnabar and massicot together with lead white and chalk in
                                                                                                                          various concentrations. In individual cases there are indications of a red lacquer, pos-
                                                                                                                          sibly carmine. XRF-analysis of the brown-red colour indicates iron and traces of zinc.
                                                                                                                          The Raman spectra show that this red contains red ochre.
                                                                                                                              Black: The contours, signatures and dates contain a mixture of iron, potassium,
                                                                                                                          copper and arsenic according to the XRF-analyses. Through microscopy, blue par-
                                                                                                                          ticles can be seen in a black matrix. With the Raman analyses we can detect carbon
                                                                                                                          black with traces of Prussian blue. No mineral green has been detected; however, the
                                                                                                                          traces of copper and arsenic can be attributed to underlying paint layers.
                                                                                                                              White: The white details contain mainly lead. Raman analysis indicates white lead
                                                                                                                          and traces of chalk. In an oil medium the presence of chalk would indicate a iller or
                                                                                                                          extender.
                                                                                                                              Binders: According to the historical documents (Table 1) linseed oil was used as a
                                                                                                                          binder in the paint of the three objects [7]. Thus, the aim of the preliminary FT-IR analy-
                                                                                                                          ses was to try to support or reject the hypothesis that linseed oil was used as the main
                                                                                                                          binder component in the Ädel samples. The preliminary FT-IR results are listed in Table
                                                                                                                          2. Lipid signatures were observed in most of the paint samples supporting the linseed
                                                                                                                          oil hypothesis in the underlying layer of the table and in some of the decorations on
                                                                                                                          both the table and on the casket. The chest did not show any signs of lipids. This might


                                                                                                                     90
be because the object had been heavily restored and had a secondary varnish on top.
However, the XRF-analyses indicate that all ROIs contain some lead, even when the
observed pigments do not contain lead. The lead content may be due to the linseed oil
having been boiled with a lead siccative such as litharge to make the paint dry more
rapidly. This strengthens the assumption that there is oil in the paint on all three objects.




Figure 2. The blue paint contains Prussian blue mixed with lead white and chalk. The casket and
the chest also contain some indigo.




                                                                                                         CONSERVATION SCIENCE IN CULTURAL HERITAGE




Figure 3. The indigotin peaks are slightly reduced and shifted probably due to deterioration [1].
The blue spectrum is a reference spectrum of Prussian blue pigment. The yellow is a chalk
reference spectrum. The olive green is a lead white reference spectrum. The red is an indirubin
reference spectrum and the blue green is an indigotin reference spectrum.


                                                                                                    91
I. Nyström, J. Thomas, Y. Fors, L. Friis, A. Assis, K. Thuresson - Forensic art history: the Ädel painting dispute




                                                                                                                          Figure 4. The Raman spectra indicate a mixture of malachite and possibly emerald green as well
                                                                                                                          as Prussian blue, massicot, lead white and chalk. The blue spectrum is Prussian blue. The green
                                                                                                                          is malachite and the yellow is massicot.


                                                                                                                          Table 1. Quantities and prices in old Swedish currency - Riksdaler Banko - of various artist’s
                                                                                                                          materials mentioned in the legal case. The italic text is the original text in Swedish.

                                                                                                                           Artist’s materials        Chemical name              Quantity               Price
                                                                                                                           Kornmjöl, barley          starch                     3 skålpund / ca        0,25 riksdaler
                                                                                                                           lour                                                 1.3 kg
                                                                                                                           Linolja, linseed oil      triglyceride: linoleic     ½ kanna / ca 1.3 l     1,50 riksdaler
                                                                                                                                                     acid, alpha-linolenic
                                                                                                                                                     acid and oleic acid
                                                                                                                           Blyhvit, white lead       basic lead carbonate       3 skålpund / ca        1,46 riksdaler
                                                                                                                                                                                1.3 kg
                                                                                                                           Berlinerblått,            hexacyano ferrate          4 lod / ca 53 g        0,59 riksdaler
                                                                                                                           Prussian blue
                                                                                                                           Malen krita, chalk        calcium carbonate          4 skålpund / ca        0,20 riksdaler
                                                                                                                                                                                1.7 kg
                                                                                                                           Ljusåker, yellow          iron oxide                 8 lod / ca 106 g       0,35 riksdaler
                                                                                                                           ochre
                                                                                                                           Mineralgrönt,             copper containing          1 lod / ca 13 g        0,35 riksdaler
                                                                                                                           Mineral green*            green pigment
                                                                                                                           Linolja, linseed oil      triglyceride: linoleic     3 kannor / ca          9,00 Riksdaler
                                                                                                                                                     acid, alpha-linolenic      7.85 l
                                                                                                                                                     acid and oleic acid
                                                                                                                           Blyhvit, lead white       lead carbonate hy-         1 lispund / ca         9,83 riksdaler
                                                                                                                                                     droxide                    8.5 kg



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 Mönja, red lead              lead (II,IV) oxide            2 skålpund /               0,83 riksdaler
                                                            850 g
 Cinnober, cinnabar           mercury (II) sulphide         3 lod / 425 g              0,19 riksdaler
 Berlineblått,                hexacyano ferrate             ½ skålpund / ca            1,50 riksdaler
 Prussian blue                                              212 g
 Möngel, litharge             tetragonal lead (II)          1 skålpund /               0,75 riksdaler
                              oxide                         425 g
 Silfverglitt, litharge       tetragonal lead (II)          ½ skålpund / ca            0,22 riksdaler
                              oxide                         212 g
 Möngel, litharge             tetragonal lead (II)          ½ skålpund / ca            0,50 riksdaler
                              oxide                         212 g
 Mönja, red lead              lead (II,IV) oxide            1 skålpund /               0,50 riksdaler
                                                            425 g
 Silfverglitt, litharge       tetragonal lead (II)                                     0,25 riksdaler
                              oxide
 Berlineblått,                iron(III)                     4 lod / ca 53 g            0,50 riksdaler
 Prussian blue                hexacyanoferrate(II)
 Wecktriol, vitriol           iron(II) sulfate              4 lod / ca 53 g            0,13 riksdaler
 Krita, chalk                 calcium carbonate             4 skålpund / 10.2          0,88 riksdaler
                                                            kg
 Linolja, linseed oil         triglyceride: linoleic        1 kanna / ca 2.6 l         3,00 riksdaler
                              acid, alpha-linolenic




                                                                                                             CONSERVATION SCIENCE IN CULTURAL HERITAGE
                              acid and oleic acid
 Hvitmjöl, white lour         starch                        1 lispund / ca             3,33 riksdaler
                                                            8.5 kg
 Linolja, linseed oil         triglyceride: linoleic        3/8 kanna / ca             1,13 riksdaler
                              acid, alpha-linolenic         0.98 l
                              acid and oleic acid

*The term “Mineral green” has been applied for various copper mineral pigments [5].

Table 2. Preliminarily FT-IR analyses to support or reject the hypothesis that linseed oil was used
as the main binder component in the Ädel samples. Lipid signatures were observed in some of
the paint samples supporting the linseed oil hypothesis. The chest was substantially restored and
varnished which may have affected the analyses.

 Sample Number            Object/Position            Colour of sample         Linseed oil
 AA 1839-1b               table/underlying           blue                     likely
                          paint layer
 AA 1839-2b               table/right side           red-brown                weak resemblance
 AA 1839-3b               table/table top            red-orange               weak resemblance


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                                                                                                                           AA 1839-4b           table/left side        red-orange            weak resemblance
                                                                                                                           AA 1839-5b          table/lower on table    red-brown             likely
                                                                                                                                               top
I. Nyström, J. Thomas, Y. Fors, L. Friis, A. Assis, K. Thuresson - Forensic art history: the Ädel painting dispute




                                                                                                                           AA 1839-6b          table/lower left side   red-brown             weak resemblance
                                                                                                                           AA 1839-7b          table/table top         green                 likely
                                                                                                                           AA 1839-8b          table/leaf left side    green                 weak resemblance
                                                                                                                           AA 1839-9b          table/table top         black                 likely
                                                                                                                           AA 1839-10b         table/left side         black                 likely
                                                                                                                           AA 1939-11b         table/table top         yellow                -
                                                                                                                           AA 1839-12b         table/table top         white                 unlikely
                                                                                                                           AA 1839-13b         table/left side         white                 weak resemblance
                                                                                                                           AA BED-1b            casket/ground co-      blue                  weak resemblance
                                                                                                                                               lour
                                                                                                                           AA BED-2b           casket/border           red                   likely
                                                                                                                           AA BED-3b           casket/lower            orange                unlikely
                                                                                                                           AA BED-4b           casket/lower            yellow-green          weak resemblance
                                                                                                                           AA BED-5b           casket/leaf             green                 unlikely
                                                                                                                           AA BED-6b           casket/plant            black                 likely
                                                                                                                           AA KST-1b           Chest/ground colour     blue                  unlikely
                                                                                                                           AA KST/1c           Chest                   blue                  unlikely


                                                                                                                            5. Conclusion

                                                                                                                              The historical documents and the protocols of this court case are a rich source of
                                                                                                                          information for art technical studies. Receipts for the purchased pigments and the
                                                                                                                          comments on the materials used by the artist for the painted furniture in this case give
                                                                                                                          an indication of the materials Ädel had access to and what he might have used in his
                                                                                                                          painting. By means of scientiic analyses, the pigments that Ädel actually used can be
                                                                                                                          identiied and compared with written sources from the period. The documents have
                                                                                                                          been used as guidance for the interpretation of the results from the scientiic analyses.
                                                                                                                          εoreover, the scientiic analyses have shown that other pigments were used in ad-
                                                                                                                          dition to those mentioned in the dispute. This is an indication that the testimony may
                                                                                                                          contain inaccurate information and that the court records must be interpreted critically.
                                                                                                                          According to the results of the analyses relating to the three objects - the chest, the
                                                                                                                          casket and the table - the paint layers contain the following pigments:
                                                                                                                              • White colour in the details and highlights consists of lead white and some chalk
                                                                                                                                as a iller/extender.


                                                                                                                     94
   • Yellow colour in the painted petals consists of a mixture of litharge/massicot and
       light ochre, sometimes only litharge/massicot, depending on the shade.
   • Red and orange colour in borders and petals consists of red ochre and a mixture
       of red lead, cinnabar and some lead white, and possibly carmine lacquer.
   • Blue underpaint consists of Prussian blue mixed with lead white and chalk, oc-
       casionally mixed with indigo.
   • Green colour in the leaves and stems in the motif are a mixture of mineral green
       containing copper, possibly malachite, mixed with emerald green containing cop-
       per and arsenic. Sometimes the green pigment is also mixed with Prussian blue
       and massicot.
   • Black colour in contours and monograms consists of a mixture of carbon black
       and Prussian blue.
   The receipts and invoices also give insight into what the different pigments cost dur-
ing the decades prior to the mid-1800s. They also show, along with the legal protocols,
the quantities of the different pigments used for the painting. The quantities have been
recalculated into a contemporary unit of measurement (Table 1) which can be used
to understand the possible usage of each material. When combined with the price of
each material a picture of high status objects prepared with costly materials emerges.
   An example of the type of information that can be extracted is that silverglitt (li-
tharge) was probably used as a drier, siccative, while möngel (litharge) would have
been used as a yellow pigment. This interpretation is based on the quantity and the
price difference between silverglitt (210 g, 10 Skilling) and möngel (425 g, 36 Skilling).
Only a small amount of litharge is needed in the boiling of linseed oil compared to the
production of yellow paint. Furthermore, as litharge/massicot has been detected in the
yellow paint, we suggest that the pigment möngel (also named mengel in Swedish), is
the yellow litharge/massicot in paint.1
   In the legal protocol, it is mentioned that Ädel worked for ive and a half days paint-
ing about 30 items including the above-mentioned furniture. The time spent on painting




                                                                                                    CONSERVATION SCIENCE IN CULTURAL HERITAGE
these objects shows that Ädel was an experienced painter and that he must have been
working quickly and eficiently. The paint on the chest, casket and table indicates that
the light blue colour is painted only in one layer, since it is partially transparent and
that the wood beneath can be distinguished. As it seems to be oil paint (lipids were
indicated in some samples), the layer should have been allowed to dry at least one
to two days before decorative painting could begin on top. One can imagine that Ädel
began by painting all the blue coloured furniture at the same time. He then decorated
them all once they were dry. Through the pigment analyses, however, we note that
Ädel has used indigo in different amounts on the chest and the casket and not at all on
the table. As indigo is not mentioned in the protocols from the court case, Ädel might
have brought this pigment along with other pigments, as well as painting materials
himself (i.e. these artist’s materials were not bought by the client). Could it be that Ädel
prepared different batches of blue paint; one with indigo mixed with the Prussian blue
and another with only Prussian blue? One can imagine a scenario where Ädel was us-
ing a ‘remainder’ of blue paint containing indigo to which he added Prussian blue, and
when this paint ran out he prepared a new blue paint using only Prussian blue. If so,
then perhaps, the chest which contains the most indigo (of the three items analysed)
would have been painted blue earlier than the table which contains only Prussian blue.
   Through scientiic analysis, we can demonstrate and support what the expert wit-
ness Blombertsson stated, that Ädel used more pigments than those which Olofsson


                                                                                               95
                                                                                                                          reports in the receipts (Table 1). Examples of such pigments are chalk, carbon black,
                                                                                                                          red ochre, two different coppers containing green pigments and indigo. There are pos-
                                                                                                                          sibly other pigments, such as iron oxide black, not mentioned in the receipt. In regard
                                                                                                                          to the analyses, we also see that Ädel frequently mixed his pigments. This is relatively
                                                                                                                          rare in a Swedish folk art context, at least if compared to Southern Swedish painted
I. Nyström, J. Thomas, Y. Fors, L. Friis, A. Assis, K. Thuresson - Forensic art history: the Ädel painting dispute




                                                                                                                          wall-hangings from the same period. Typically, Swedish folk painters used one brush
                                                                                                                          for each paint and seldom mixed the different paints to achieve a particular hue. Ädel,
                                                                                                                          on the other hand, rather seems to search for the right hue and thus mixes several
                                                                                                                          paints to achieve it.
                                                                                                                              As a conclusion from this study, we believe that cooperation between different dis-
                                                                                                                          ciplines is crucial to tackle and interpret this kind of empirical material which contains
                                                                                                                          both historical sources that require transcriptions and interpretations, and material
                                                                                                                          characterization and scientiic interpretation of the results. When different skills and
                                                                                                                          various perspectives come together, new interpretations and knowledge can be ob-
                                                                                                                          tained. The gathered knowledge can also be crucial for future conservation and pres-
                                                                                                                          ervation, as some of the pigments in the objects contain toxic arsenic, lead and copper.
                                                                                                                          It is therefore important to take into account this factor when conservators and curators
                                                                                                                          handle this type of object during their work.


                                                                                                                             Acknowledgements

                                                                                                                              The presented study is part of a larger interdisciplinary project “Decorated Farm-
                                                                                                                          houses of Hälsingland: A holistic study of a world heritage site”, in which methods
                                                                                                                          from natural and historical sciences are applied to the decorative folk arts and crafts
                                                                                                                          in the farmhouses of Hälsingland, UNESCO World Heritage. The project is four years
                                                                                                                          long and funded by the Swedish Research Council (VR). The study is a collaboration
                                                                                                                          between different researchers: conservation scientists, chemists, physicists, conserva-
                                                                                                                          tors, art historians and ethnologists and the project participants are:
                                                                                                                              Ingalill Nyström, project leader, PhD conservation science, Dep. of Conservation,
                                                                                                                          University of Gothenburg; Anneli Palmsköld, assistant professor, ethnology, Dep. of
                                                                                                                          Conservation, University of Gothenburg; Jacob Thomas, PhD conservation science,
                                                                                                                          Dep. of Conservation, University of Gothenburg; Yvonne Fors, PhD chemistry, Dep. of
                                                                                                                          Conservation, University of Gothenburg/ The Swedish National Heritage Board; Johan
                                                                                                                          Knutsson professor, art history, Carl Malmsten furniture studies, Linköping University;
                                                                                                                          Kaj Thuresson, PhD chemistry, The Swedish National Heritage Board; Thomas Zack,
                                                                                                                          assistant professor, geology, Earth Science, University of Gothenburg; Aleksandar
                                                                                                                          Matic professor, physics, Applied Physics, Chalmers; Liv Friis, BSc, paper conserva-
                                                                                                                          tion, Dep. of Conservation, University of Gothenburg; Anders Assis, antiquarian, Ljus-
                                                                                                                          dalsbygdens museum.
                                                                                                                              The project is also collaborating with other experts who include:
                                                                                                                              Sven Isaksson, assistant professor, archaeological science, Archaeological Re-
                                                                                                                          search Laboratory, Stockholm University; Lars Nylander BSc art history, antiquarian,
                                                                                                                          Hälsinglands museum, Hudiksvall; Mélanie Platzgummer BSc, World heritage coordi-
                                                                                                                          nator Bollnäs county, Culture department.




                                                                                                                     96
      Notes
1
  The word möngel could be a name for yellow mönja (red lead), where the preix “mön” is used
in combination with the sufix “gel” from the German term for yellow gelb. The other name mengel
could originate from Dutch, where red lead is called mennia and yellow is gel. Whatever the deri-
vation of the name, möngel is a yellow lead oxide.



      References

[1]     Nyström, I., Wilken, S., and Thomas, J. (2016). FT-Raman analyses of Blue dyes
        stuff common in Swedish folk art from Hälsingland during 18th and 19th century.
        Chemical Sciences Journal 7(2).
[2]     Tronner, K., Nord, A.G., von Arronet, D., and Mattsson, E. (2003). Nils Månsson
        Mandelgrens färgämnessamling: Dokumentation och analysresultat. Riksan-
        tikvarieämbetet 31. Stockholm, p. 14.
[3]     Tronner, K., Nord, A.G., von Arronet, D., Mattsson, E., and Brandi, A. (2006).
        Undersökning av en unik färgprovsamling på Kungl. Konsthögskolan. Dokumen-
        tation, analys och sammanfattning. Rapport från Riksantikvarieämbetet 2006:1.
        Stockholm, p.28.
[4]     Post-och inrikestidningar 1832: 19
[5]     Eastaugh, N. (2008). Pigment compendium: a dictionary and optical microscopy
        of historical pigments. Butterworth-Heinemann: Oxford, pp. 234, 247, 262, 269.
[6]     Karlsdotter Lyckman, K. (2005). Historiska oljefärger i arkitektur och restaure-
        ring. Diss. Stockholms universitet. Vara: Färgarkeologens förlag, pp. 70, 83.
[7]     Lyckman Gevert, K. (2016). Målarmästarens längtan. Byggnadskultur 1:16, pp.
        12-17.




                                                                                                         CONSERVATION SCIENCE IN CULTURAL HERITAGE
      Archive sources

      Landsarkivet Härnösand (HLa):
      Domstolsarkiv:
      Hälsingland, Ljusdals tingslags häradsrättsarkiv
      A1a:17 Dombok 1838-1839          Vårting 1839, §67
      A1a:17 Dombok 1838-1839          Höstting 1839, §45
      A1a:18 Dombok 1840               Vårting 1840, §55
      A1a:18 Dombok 1840               Höstting 1840, §48
      A1a:19 Dombok 1841               Vårting 1841, §48
      FIII:1 konkursakter              Konkurs nr 11, år 1840

      Västernorrlands lagmansrätt:
      Akter 1841 för Hälsingland och Härjedalen              Stämningslista


      Biographical notes

  Ingalill Nyström is an associated professor and researcher at the Department of
Conservation, Gothenburg University. She is the project leader of the project Decorat-


                                                                                                    97
                                                                                                                          ed Farmhouses of Hälsingland: A holistic study of a World Heritage site, founded by the
                                                                                                                          National Research Council in Sweden (Vetenskaps Rådet). She received her master’s
                                                                                                                          degree in conservation in 2003 and her PhD degree in 2012 on the thesis “Spectro-
                                                                                                                          scopic Analysis of Paint and Technique in Southern Swedish Painted Wall-hangings
                                                                                                                          1700-1870” at the Conservation Department, Faculty of Science, Gothenburg Univer-
I. Nyström, J. Thomas, Y. Fors, L. Friis, A. Assis, K. Thuresson - Forensic art history: the Ädel painting dispute




                                                                                                                          sity. Nyström has studied analytical chemistry and she has long experience as a paint-
                                                                                                                          ing conservator. Her main focus is historic art technology using spectroscopic analyti-
                                                                                                                          cal methods such as FT-Raman, FTIR, SEM-EDX and Multispectral Imaging.

                                                                                                                              Jacob Thomas is an assistant professor researcher in heritage science at the Depart-
                                                                                                                          ment of Conservation, Gothenburg University. His PhD in sustainable heritage from Univer-
                                                                                                                          sity College London with the Tate Gallery focused on how the oxygen-free display of works
                                                                                                                          on paper can be used to meet preservation targets and how to evaluate this with instrumen-
                                                                                                                          tal analysis: headspace GC-MS, XAS, UV-Vis-FORS, and chemiluminometry. He has also
                                                                                                                          worked in a research team developing multifunctional nanocomposite packaging materials.
                                                                                                                          He is generally interested in developing both ‘high’ and ‘low’ tech diagnostic methods for the
                                                                                                                          heritage sector. In this project, Thomas works with ambient pressure chemical ionisation
                                                                                                                          mass spectrometry to identify organic colorants in heritage materials.

                                                                                                                             Liv Friis is a research engineer, conservator and master student at the Department
                                                                                                                          of Conservation at Gothenburg University. She has an undergraduate degree in Con-
                                                                                                                          servation from Gothenburg University (2014), with a specialization in paper objects.
                                                                                                                          Her previous studies focus on light fastness of ink on prints using micro fading testing.
                                                                                                                          Since January 2016, Friis has been assisting the research project. She manages the
                                                                                                                          projects database and runs pigment analysis using Raman spectroscopy.

                                                                                                                             Yvonne Fors is a chemist and works as a scientist at the Department of Con-
                                                                                                                          servation, University of Gothenburg and as a project manager concerning preserva-
                                                                                                                          tion issues at the Swedish National Heritage Board. Fors had her doctoral degree in
                                                                                                                          structural chemistry at Stockholm University in 2008 with a thesis about preservation
                                                                                                                          challenges with marine archaeological wood. Fors’ part in the project is to analyze
                                                                                                                          the binders used in the paintings. FT-IR (Fourier Transform Infrared Spectroscopy)
                                                                                                                          offers a general idea about the basic compounds of the samples, such as lipids, car-
                                                                                                                          bohydrates, starch or protein. Thereafter the samples are analyzed with GC-MS (gas
                                                                                                                          chromatography-mass spectrometry) to gain more detailed information about what
                                                                                                                          binder/binders has/have been used. The analyses are carried out at the Archaeologi-
                                                                                                                          cal Research Laboratory, Stockholm University.

                                                                                                                             Anders Assis is an antiquarian at Ljusdalsbygdens museum in Hälsingland. The
                                                                                                                          institution has been working with research about the regional painting traditions in
                                                                                                                          decorated farmhouses in the region and its practitioners since 1985. Assis has been
                                                                                                                          responsible for this work since 2005. His main work for the project is historical source
                                                                                                                          research in archives and stylistic analyses of painted objects. Assis puts the research
                                                                                                                          objects in their local and cultural context and assists the project in contact with the
                                                                                                                          stake holders at the world heritage sites, Decorated Farmhouses of Hälsingland.

                                                                                                                            Kaj Thuresson is employed as a researcher and chemist at the Department of
                                                                                                                          Conservation Science, National Heritage Board. Thuresson received his PhD degree


                                                                                                                     98
in Environmental Chemistry at Stockholm University. For eight years Thuresson has
been working with conservation science in the cultural conservation sector. His exper-
tise is in chemical analysis and materials. In the project Thuresson assists with sam-
pling and sample analysis using techniques such as XRF and Raman.



   Summary
   This article concerns a 19th century dispute about twenty pieces of decorated fur-
niture painted by the 19th century painter Anders Erik Ädel (1809-1888) from Söder-
hamn, Hälsingland, Sweden. Ädel is considered to be one of the foremost painters in
Hälsingland. His art works - painted furniture and interiors - are displayed in museums
and can also be found in the Decorated Farmhouses of Hälsingland, UNESCO World
Heritage. In 1839, Ädel accused his client, the farmer Erik Olofsson, in court of having
paid too little for the objects he had painted as he had used more pigments than those
for which he had been paid. Almost 180 years later scientiic methods combined with
historic source research were used to understand what pigments Ädel actually used.
Through this study we demonstrate how multidisciplinary collaboration between sci-
ences and humanities can contribute to deeper knowledge and new interpretations.
The scientiic analyses were preceded by analyses of the judicial protocols found.
Non-invasive analyses using XRF instruments were conducted in situ, supplemented
by other spectroscopic methods in the lab. The judicial protocols give an insight into
what pigments Ädel had access to, and when combined with the scientiic analyses,
this information provides historic evidence of the artist’s materials and painting tech-
nique.

    Riassunto
    Il presente articolo riguarda una disputa del XIX secolo riguardo circa venti oggetti




                                                                                                   CONSERVATION SCIENCE IN CULTURAL HERITAGE
di arredo dipinti da un pittore del XIX secolo Anders Erik Ädel (1809-1888) da Söder-
hamn, Hälsingland, Svezia. Ädel è considerato uno dei più importanti pittori in Hälsing-
land. Le sue opere, costituite da oggetti di arredo e interni dipinti, sono esposte nei mu-
sei ed è possibile fruirle nelle Decorated Farmhouses of Hälsingland, UNESCO World
Heritage. Nel 1839, Ädel accusò un suo cliente il fattore Erik Olofsson in tribunale, per
averlo retribuito troppo poco per gli oggetti che egli aveva dipinto, in quanto aveva
utilizzato più pigmenti rispetto a quelli per i quali egli era stato pagato. Quasi 180 anni
più tardi, le metodologie scientiiche insieme con la ricerca delle fonti storiche, hanno
permesso di conoscere quali pigmenti Ädel effettivamente utilizzò. Con questo studio
si fa presente come la collaborazione interdisciplinare tra le scienze e gli studi umanis-
tici possano contribuire ad una conoscenza più approfondita e a nuove interpretazioni.
δe indagini scientiiche, precedute dallo studio dei protocolli giuridici ritrovati, sono
state condotte in situ mediante XRF e in laboratorio con altri metodi spettroscopici. I
protocolli giuridici con la ricerca scientiica forniscono informazioni su quali pigmenti
Ädel abbia impiegato, costituendo in tal maniera testimonianza storica dei materiali e
della tecnica pittorica dell’artista.




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