ISA 2012 Daniel et al

Proceedings of the 39th International Symposium for Archaeometry, Leuven (2012) 329-334
Of some blue and bluish-grey pigments (“false blue”)
in medieval mural paintings in the South West of France
F. Daniel1, A. Mounier1, P. Ricarrere2
1.
Centre de Recherche en Physique Appliquée à l’Archéologie, IRAMAT UMR 5060-Université de Bordeaux3/ CNRS,
[email protected]
2. CESCM– UMR 6223– CNRS Université de Poitiers,
[email protected]
The primitive Saint-Nicholas church in Nogaro (11th
century, Gers) was built in 1060 and the murals are dated to
the end of the 11th century. These are preserved in the chevet
of the building, in the apsidioles. The paintings in the south
apsidiole were discovered in 2004 during a restoration
campaign. The represented iconographic theme is ‘Christ in
Majesty surrounded by the Tetramorphous’. The ‘Christ in
Majesty’ corresponds to the glorious Christ image,
enthroned between the four evangelistic symbols: lion for
Mark, ox for Luke, man or angel for Matthew, eagle for
John. God is represented by a man on a throne in a
mandorla, raising the index and the major fingers of the
right hand and handing a book in his left hand. An angel is
paint in the north and south extremities.
ABSTRACT
Due to the lack of availability of raw materials, the blue
colour is little used before the 12th century in medieval
mural paintings. The pallet consists of more accessible
pigments such as black (calcination of organic materials),
white (lime), and the various nuances from yellow to red
obtained with ochre. When blues were used, they were
imported from Germany (azurite) or Afghanistan (lapis
lazuli). This made these colouring materials expensive and
they were reserved for important zones of the painting. The
blue colour changes its status in the 12th century. It settles, in
iconography, as the colour of the mantle of the Virgin,
which in return conferred to this colour a particular
symbolic value. The use and choice of blue pigments was
guided by economic constraints, local availability and,
naturally, iconographic choices (symbolic relationships,
hierarchy of colours).
The murals of the ancient chapel of the abbatial house in
Moissac, dated to the 12th century are preserved on the vault
of the chapel. Only the north part of the vault kept its
decoration. The juxtaposition of the ‘Tree of Jesse’ and
‘Christ in Majesty’ surrounded by the apostles (Czerniak
2003, 2004) is associated with the royal ancestry of Christ,
placed in his genealogy of Jesse, father of King David.
KEYWORDS
Aerinite, Blue, Mediaeval, Mural paintings, Pigments.
The diversity of materials is a significant source of
information on the relationship between colour and
representation; on the economic aspects or the circulation of
materials or workshops. Blue is a little used colour on
paintings in the Middle Ages before the 12th century
(Pastoureau 2000). In the symbolism of the High Middle
Ages, this colour is little valued. Yet after the 12th century,
blue becomes aristocratic. We especially see it in clothes;
Royal Blue is the colour of the king of France and it is
associated with the Virgin image. After this date, its
evolution, use and development increase. Contrary to other
colours, for which the raw material was available and cheap,
the use of blue was limited according to origin or cost.
The construction of the Romanesque cathedral of SaintEtienne, in Cahors, took place between 1109 and 1140. The
paintings on the portal of the western facade are made from
traces of polychromy and gildings on the architectural
elements by two painted figures. The characters hold
musical instruments. The arches of the portal are also
painted and sometimes alternate the blue, red, green and
white with red and grey flowers. This decoration dates to the
end of the 13th century or the beginning of the 14th century,
and was never restored (Czerniak et al. 2007).
The construction of the Saint-Andre Cathedral of Bordeaux
was between the 11th and 16th centuries. The Sainte-Anne
chapel was built in the 14th century. The painted decoration
is organized in three horizontal sections which occupy the
high and central parts of the wall. The top represents the
celestial universe. It is decorated with a central shining sun
representing God in glory (Gaborit 1997). The middle zone
is vertically divided into two panels: a Crucifixion scene is
represented to the left, the Virgin with the Child to the right.
The Christ is surrounded by a multitude of angels.
Experimentation
Sites and sampling.
Seven mural paintings from the 11th to the 15th centuries,
situated in the Southwest of France, were chosen as
examples of the diversity of the blue pigments used in the
mediaeval period. Samplings were made of blue colours
(Table 1).
!
The paintings in Beynac Castle (Beynac-et-Cazenac,
Dordogne) are situated in the chapel, close to the Room of
the States of Périgord. The small oratory was completely
329
decorated in the 15th century with frescoes, among which a
Pietà.
The presence of aerinite on the paintings of the chapel in
Moissac, allows the hypothesis of the circulation of this
material through the Pyrenees, doubtless by an itinerant
workshop which would have worked in the Romanesque
period on diverse sites of the South of France (Moissac,
Nogaro) (Daniel et al. 2008).
The Saint-Christophe church in Montferrand-du-Périgord
(Dordogne) shows arch-stones which alternate blue, yellow
and red. Several characters are also represented with blue
clothes, one of whom is the ‘Virgin of the Annunciation’.
The house of 22 Labat Street (Belooussoff House), in
Marmande, was dated of the end of the 15th century. On the
first floor, remains of "blue" painting on cob are still visible.
On the "blue" layer, elements of decoration (scrolls, false
stones) are painted in white. The pictorial layer goes from
blue to black in places but the aspect of the whole seems
blue grey.
The blue pigments in Cahors (bright blue and turquoise
blue) are of azurite (brass carbonate).
“Classic” blue: Azurite and Lapis-Lazuli
In medieval mural paintings, most of the blue pigments
result from non-local sources of colouring materials. The
most frequently used are generally copper based pigments or
rare and expensive pigment like lapis-lazuli.
Methods
Azurite is a copper carbonate (Cu3(CO3)2(OH)2). This
pigment, used in ancient Egypt, is cheaper than lapis-lazuli
but has less stability. In the Middle Ages, it is extracted
from Germany and Bohemia. Its extraction takes a long time
and the production of powder, for its use as a pigment, is
difficult.
Analysis of the colour: the reflectance spectra and the
chromatic coordinates are obtained thanks to a Minolta
CM2600D spectrocolorimeter (observation angle 2°,
illuminant D65).
Examination and physico-chemical analysis of the paintings:
the examinations and the surface texture were realized by
means of a binocular coupled with a digital camera, piloted
by the software of acquisition "Analysis ". The elementary
analysis is performed with SEM/EDS (Jeol JSM-6460LV
associated with an X-ray microanalysis INCA OXFORD
300) allowing a quantitative chemical analysis. The
identification of pigments is done by Raman micro
spectrometry (Renishaw RM 2000).
Lapis-lazuli or ultramarine is the most important blue
pigment in the Middle Ages (Barnett et al., 2006). It results
from the grinding of a semiprecious mineral made of
lazurite, calcite and pyrite (Na,Ca)8[(S,SO4Cl)2 (AlSiO4)6].
The ultramarine pigment is often used for the Christ figure
or the Mantle of the Virgin and it was very often associated
with gildings. Lapis-lazuli is the most expensive pigment. It
is said that over-seas, it costs its weight in gold (Délivré,
2006). The lapis-lazuli quality and price depend on the
granulometry. Its colour varies from blue-purple to
greenish-blue. The broken stone gives a bluish blue but it is
only without impurities which gives a sharp blue.
Results and discussion
The results are given in Table 2. The blue pigments can be
classified into three categories: the classic pigments, the
blue of local origin and that which we called "false blue".
Azurite and lapis lazuli are located in cathedral paintings
such as in the Sainte-Anne chapel of the Saint-Andre
cathedral in Bordeaux or on the portal of the Saint-Etienne
cathedral in Cahors. These two types of blue pigment allow
the emphasis of certain zones, such as the blue sky where
the sun represents God in Glory (Bordeaux) or arches and
painted figures (Cahors).
Local Blues
- In symbolically important zones of the image, such as the
mandorla and for some important characters: evangelists (St
Luke's ox in Nogaro, St Mark's lion in Moissac) or the
virgin coat in Beynac, for example. Generally we find in
these zones the classic blues but it is also possible to see
"false blue" there.
- In the backgrounds (Nogaro, Moissac, Cahors) and
architectural elements (false stone, arch-stones). The
pigments used in this case are less expensive: blues of local
origin (aerinite) or "false blues".
In chapels or churches, such as in Moissac or Nogaro, the
blue is very present and appears under at least three different
nuances of colour. Bright blue (lapis lazuli) is located in the
scenes where the spirituality is the strongest: the Christ and
the Virgin. Azurite is present in several places, in particular
in the Virgin mandorla.
We observe a hierarchical organization of the blue
pigments: in the Nogaro paintings, the lapis lazuli is
reserved for Christ in Glory whereas aerinite will be used
for the Tetramorphous.
Aerinite: a local resource
From the 12th century, the extension of the use of blue
colours meant that people had to look for cheaper materials.
It explains the recourse to particular sources of local
pigments such as aerinite, deposits of which are very limited
and situated in the region between Aragon and Catalonia.
In Moissac, we found three types of blue pigment: lapis
lazuli for the bright blue, localized in the important zones
(Christ Pantocrator), azurite for the ‘Virgin in Majesty’ and
aerinite for the background decorations. By economy, the
lapis lazuli is applied on an aerinite or on a carbon black
layer.
!
This pigment was abundantly used in the North of Spain.
We recently found examples of its use in France (Daniel et
al. 2008). On material and stylistic arguments, we can
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suppose that these pigments were imported by itinerant
workshops.
colour contrast, the local tone is dependent on the
colour of the surrounding objects. For any perceived
colour, the brain creates a complementary tone. The eye
tends to create the missing colour (the complementary) to
form a neutral balance in our brain. In some of the paintings,
orange elements (obtained by a mixture of yellow and red)
are juxtaposed to a grey colour and this creates a bluish
tone.
It is an aluminium and calcium hydrated silicate. Its blue
colour would come from the iron present in the matrix and
in particular depends on the Fe2+/Fe3+ ratio (Portat et al.,
1990). The tone varies from light to very dark blue. This
mineral can be found in the Spanish Pyrenees, in the regions
of Huesca (Estopinan del Castillo, Juseu, Nacha) and of
Lerida (Avellanes, Hostalets de Tost), but also in Morocco
(Azambre & Monchoux, 1988) and in France, in SaintPandelon (Landes).
Indefinite grey blue
This grey seems to us bluish today, but no argument proves
that this was the intention of the painter. However, Buyle
mentions the example of the architectural elements of the
church of the convent, of the Dominicans in Louvain,
painted in grey-blue "to imitate the blue stone" (Buyle
2006). An example of the use of this false-blue can be found
on the first floor of the mediaeval house in Marmande, the
initial arrangement of which would date to the end of the
15th century, where a false stone is drawn in white on a grey
blue background (Ricarrère 2008; Ricarrère & Laroche, in
press).
In Moissac, aerinite has been used in all the background of
the floral decorations, and in Nogaro to represent certain
haloes of the evangelic symbols.
“False blue”: A typology
Except for these "objective" blue pigments characterized by
their nature, mixtures of cheap pigments (essentially white
and black) have been employed for economic, aesthetic and
iconographic reasons. This creates visibly grey coloured
areas, which are considered blue. Yet, in the Romanesque
period, the black appears under various tones: matt, brilliant,
light, deep black, brown or blue (Pastoureau, 2008). It is
particularly used to encircle the characters, raise them or for
friezes and geometrical forms. It is rarely used as a uniform
colour layer and finds itself preferentially on negative
representations, such as, hell, associated with red. For
example, we find it on the image of the devil (between the
11th and the 13th centuries). In contrast, the black was often
used, until the 12th century, for the Virgin Mantle,
traditionally to represent it in a dark colour (Pastoureau
2008).
Another means consisted of using a mixture of pigments
reproducing a coloured bluish-grey effect. They are visually
grey (a mixture of carbon black and calcite - we also find,
there, tracks of ochre) as confirmed by colour
measurements. They are called blue because of the
perception we have of them. These "false blues" were
observed in several sites in the southwest of France between
the 12th and the 14th centuries and we suggest a classification
in three categories, some examples of which include:
"Semantic blue"
These kind of greys are spontaneously named blue because
what they represent is symbolically blue (sky, Mantle of the
Virgin, sea). It is a case where we can legitimately suppose
that the intention of the painter was to give the illusion of a
blue colour. The colorimetric measurements show that the
grey-blue zones of the paintings of Beynac Castle is in
reality, neutral grey. The blue perception that we have of it,
can be due to the semantic context for the Virgin Mantle.
Fig. 1. Beynac castle, Pieta (15th century).
The question of the "false blues", from which we were able
to distinguish several types, is rarely mentioned. Although,
some recent references state it. An article of PalazzoBertholon begins with the report of some analyses of the use
of "false blue" in the paintings from the 8th to the 10th
centuries (Palazzo-Bertholon 2005). This use had not
previously been indicated. These mixtures are intended to
produce the illusion of the blue colour. Similarly,
Pastoureau mentions a "blue Devil" represented on the
painted ceiling of the church of Zillis (Switzerland) from
1120-1125 (The theme is the temptation of Christ in the
desert). It would appear to be a dark grey colour (Pastoureau
2008). In the case of the "false blue", it is not only a
question of imitation. We know other examples where
Blue due to simultaneous contrast
This grey is perceived as blue because of the nearness of
complementary colours, as in the case of the arch-stones in
Montferrand-du-Périgord. It is possible that, empirically, the
painters understood that the juxtaposition of the colours
could produce this perception. In this case it would be an
ancient application of the phenomenon described by
Chevreul in 1839. According to the law of simultaneous
!
331
techniques are used to give the illusion of prestigious
materials, as is the case with the false gildings in the
medieval paintings (Mounier et al. 2009). In the case of the
grey blue, it is an application of a different conception of
colour in the medieval period. The theory comes from
Aristote in his “Treaty of the sensation and the sensitive
things”. In this philosophy, colours are classified only by
their luminosity between the white and the black. There are
only two primary colours, white and black. The other
colours can be only a precise mixture of these two colours.
The black could thus be considered as the darkest of the blue
colours. We also know that brightness and darkness were
dominating notions with regard to tints (Pastoureau 2004).
Conclusion
In the Middle Ages, the blue colours are mostly imported
from Germany or Afghanistan. Due to their relative
expensive, they are reserved for symbolically important
zones of the paintings. With the exception of well-known
colours in the medieval paintings, certain blues were
obtained from local resources as aerinite or "false blues", a
mixture of pigments reproducing a coloured bluish-grey
effect. These "false blues" were observed in several sites in
the southwest of France and deserve particular attention
because of their relation with the theory of colours and the
perception questions which they raise. In the Medieval
period, false-blues were used because some greys could be
perceived as bluish, this can also be explained by
contemporary colour theories.
Fig. 2. Montferrand-du-Périgord (Dordogne), SaintChristophe Church (12th century). Alternate use of “blue”,
yellow and red arch-stones.
Fig. 3. Chromatic coordinates (a*, b*) of different blue pigments: aerinite, azurite,
lapis-lazuli as well as the false-blue identified on the Virgin mantle in Beynac.
!
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Table 1. Sampling from the paintings and localization.
Site
Date
Sample
10453
10084
15580
15581
15584
10111
Zone in the image
Head of the ox
Blue, posterior overpainting
above an angel
Mandorla of the Christ
Behind a gilded star
Background on the right of
the Christ head
Haloe of the lion
Background behind a volute
Background behind a volute
Haloe of the lion
Background, scene of angel
Gabriel
Background, scene with
Christ
Background behind a volute
Mantle of the Virgin
Dress of the Virgin
Archstone
Background, behind a flower
10112
Background, behind a flower
10452
Nogaro
XIth c.
10457
10450
10460
Moissac
10073
10083
10084
10073
XIIth c.
10075
10078
Montferrand-du
-Périgord
Cahors
Cath.
Bordeaux,
St-André
Cath.
Marmande
Beynac,
Dordogne
XIIth c.
XIIIth c.
XIVth c.
XVth c.
XVth c.
9454
12457
12459
12460
12461
12461
15549
15552
15553
15554
cathédrale Saint-Etienne de Cahors : une étude
pluridisciplinaire, Mémoires de la Société Archéologique du
Midi de la France, t. LXVII, p. 97-112.
Daniel, F., Laborde, B., Mounier, A., Coulon, E., 2008. Le pigment
d’aérinite dans deux peintures murales romanes du sud-ouest
de la France, Archéosciences – Revue d’archéométrie, 32, 8391.
Délivré J., 2006, Les comptes des Ducs de Bourgogne à la fin du
XIVe siècle. Les noms et les prix des pigments, Couleur et
Temps – La couleur en conservation et restauration, 12e
journées d’études de la SFIIC, Paris, Institut National du
Patrimoine, 22-23 juin 2006.
Mounier A, Daniel F., Bechtel F., 2009, L’illusion de l’or –
Imitation de dorures dans les peintures murales médiévales,
Archéosciences – Revue d’archéométrie, 33 : 397-404.
Palazzo-Bertholon B., 2005, Les peintures de Saint-Pierre-LesEglises sont-elles carolingiennes? Le nouvel éclairage des
datations au radiocarbone, Rev. Hist. Du Centre-Ouest, t. IV,
2e semestre 2005, p. 335-349
Palet Casas, A. and Andres Llopis J. D., 1992, The identification of
aerinite as a blue pigment in the Romanesque frescoes of the
Pyrenean region, Studies in Conservation, 37 n°2: 132 à 136.
Pastoureau M., 2000, Bleu, histoire d’une couleur, édition du Seuil,
Paris, 215p.
Pastoureau M., 2004, Une histoire symbolique du Moyen Âge
occidental, Seuil, collection La librairie du XXIe siècle, Paris.
Pastoureau M., 2008, Noir, Histoire d’une couleur, édition du
Seuil, Paris, 210p.
Porta E., Palet A., Guillamet E., 1990, Le bleu aérinite : un
pigment méconnu en peinture murale romane, Proceedings
ICOM-CC Conference, Vol.2, p. 534-538.
Ricarrère P., 2008, Les décors peints domestiques en Aquitaine
(XIIIe-XVIe siècles) : un premier bilan, Actes des Journées
d'études : Le décor peint dans la demeure au Moyen Âge,
Angers, 15 et 16 novembre 2007 :
http://www.cg49.fr/culture/peintures_murales/journees_etudes/
journees_etudes.asp
Ricarrère P., Laroche J., in press, Les peintures murales médiévales
de l’église Saint-Sulpice de Lafosse (Gironde) – Revue
Archéologique de Bordeaux.
Scene of the Glory, over
clouds and of a musician
angel
False stone
Joint, false stone
Joint, false stone
False stone
False stone
Mantle of the Virgin
Mantle of the Virgin
Central character
Curtain
Acknowledgements
This work was funded by the program of the Working Community
of the Pyrenees (CTP) “Natural resources in the architectonic
heritage in mountain zones. Exploitation, use, analysis and
development”. (Regions : Catalonia, Aragon, Basque Country,
Midi-Pyrénées and Aquitaine).
References
Aristote, Psychologie. Opuscules : traité de la sensation et des
choses sensibles, chap. III, traduction de J. Barthelemy SaintHilaire, 1847, Paris, Dumont, 445p.
Azambre B., Monchoux P., 1988, Précisions minéralogiques sur
l’aérinite : nouvelle occurrence à Saint-Pandelon (Landes,
France), Paris, Bulletin Minéralogie., Vol.111, N°1, p. 39-47.
Buyle M., 2006, La joie des polychromies médiévales. Une
polychromie architecturale du XIIIe siècle dans la sacristie de
l’église des Dominicains de Louvain. Actes du colloque SFIIC,
Couleur & Temps : La couleur dans la Conservation et
Restauration, 21-23 juin 2006, Paris.
Chevreul M. E., 1839, De la loi du contraste simultané des couleurs
et de l'assortiment des objets colorés et de l'assortiment des
objets colorés considérés d'après cette loi dans ses rapports
avec la peinture, les tapisseries. Paris : Pitois-Levrault 1839
(721p), rééd. Paris : Léonce Laguet (1969).
Czerniak V., 2003, Les peintures murales de la chapelle de l’ancien
logis abbatial de Moissac. Un exemple méridional de
l’influence des Plantagenêt ? Mémoires de la Société
Archéologique du Midi de la France. t. LXIII, p. 75-88.
Czerniak V., 2004, La peinture murale médiévale en Quercy (XIIeXVIe siècle), thèse de doctorat, 4 volumes, Université
bordeaux 3, Pessac.
Czerniak V., Stouffs J.-M., Tessariol M., Daniel F., 2007, Les
figures peintes et la polychromie du portail occidental de la
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Appendix: Table 2. EDX elemental analysis, Raman analysis and identification of the pigments of
the painting samples (P: pictorial layer; CP: Under-layer; B: Posterior over-painting).
Blue pigment
Ref.
(BDX)
Sample location
Nogaro, XIth c., Gers
10453
Halo, head of the ox
Blue posterior overpainting, above an
10452
angel
MEB/EDS
RAMAN
Ca, Si, Fe, Al, Mg, (Na)
Aerinite
P
Ca, Fe, As, Al, Si, Cl
Azurite
B
1
Azurite
calcite
Azurite
P
1
CP
1
Lapis
Lazuli
10450
Behind a gilded star
Ca, Cu, Si, Fe, S, Al,
(Mg)
Cu, Pb, Ca, Si
10460
Background on the right of the Christ
head
Ca, Si, Al, Na, S,
(Mg),(Cl)
10457
Mandorla of the Christ
Moissac, XIIth c., Tarn-et-Garonne
10073
Haloe of the lion
10083
Background behind a volute
10084
Background behind a volute
Si, Al, Mg, Na, K, Ca, Fe
Si, Al, Mg, Na, K, Ca, Fe
Si, Al, Mg, Na, K, Ca, Fe
10073
Haloe of the lion
Si, Al, Na, S
10075
Background, scene of angel Gabriel
Si, Al, Na, S
10078
Background, scene with Christ
Si, Al, Na, S
10084
Background behind a volute
Si, Al, Na, S
Montferrand-du-Périgord , XIIth c., Dordogne
15580
Mantle of the Virgin
15581
Dress of the Virgin
15584
Archstone
Cahors, XIIIth c., Lot
10111,
10112
Background, behind a flower
Comment
+ calcite
Lead
white
Layer
A
e
r
i
n
i
t
e
CP
P
CP
Ca, Si, Al
Si, Al,Ca Fe, S, Cl
Ca, Si, Al, Mg, Cl
Azurite
1
1
1
1
P
1
P
1
P
1
P
1
P
P
P
Cu, Ca, Si
Azurite
Underlay
er dorure
à l’étain
Black
Carb.
+
calcite
1
P
Aerinite
Aerinite
Aerinite
Lapislazuli
Lapislazuli
Lapislazuli
Lapislazuli
Lapislazuli
1
1
1
CP
2
Barium
sulfate
P
1
Bordeaux, XIVth c., St-André, Gironde
9454
Scene of the Glory, over clouds and of
a musician angel
Azurite,
baryte
Cu, Ca, Si, Ba
th
Marmande, XV c., Gers
12459,
12460
Joint, false stone
Ca Si, Cl, S, Al, Na
Calcite +
salts
P
2
12457,
12461
False stone
Ca, Si Cl, S Mg, Al, Fe
Calcite
P
2
12461
False stone
Ca, Si, Al, Mg Cl, Na, K
P
CP
1
Mantle of the Virgin
Ca, Si, Al, Na, Cl, K, S
P
2
Central character
Curtain
Ca, Si, Al, S, Cl, K, Fe
Ca, Si, Al, Cl
P
P
1
1
Beynac, XVth c., Dordogne
15549,
15552
15553
15554
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334