moro, f. y pujia, a. newly mortars in mosaic restoration. 2010

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The newly applied mortars in mosaic restoration 2

CeROArt, 6 | 2010

Fabiana Moro et Angelica Pujia

The newly applied mortars in mosaicrestoration

The Dionysos mosaic in Cologne, a case study and an example to facethe problems connected to the choice of mortars and how they canchange the visual perception of mosaics.

Introduction

1 This study on the Cologne Dionysos mosaic has been prompted by its recent restoration

completed in July 2008, thanks to a cooperation between the University of Erfurt unit lead

by Dr. Christoph Merzenich and the Laboratory for Restoration of Mosaic and Stucco of the

ISCR in Rome1.

2 This German-Italian cooperation is rooted in a previous one: by the end of the fifties, the

extremely poor conservation status of the mosaic prompted the German authorities to requesta new expertise and then to commit a new intervention from the Istituto Centrale del Restauro.

Cesare Brandi personally supervised the operation, which took place in the years 1959-61; he

realized that the only feasible solution for the conservation of the floor mosaic appeared to be

the detachment of the mosaic, which was by gently pealing it from the substrate, putting it on

a roll and subsequently repositioning it in its original location, which had been duly prepared

with an inside ventilation system running below the mosaic setting bed in its final exposition

basin (ill. 1)2.


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Fig.1 The Dionysos mosac

Ill. 1 The Dionysos Mosaic, Rmisch-Germanisches Museum, Cologne.

Crdit: F. Moro

A conservative history of the Dionysos mosaic

3 In May 1941, in the middle of the second world war, the construction was begun of an anti-

air raid bunker along the South side of the Cologne cathedral; in the month of July of the

same year, in the course of the digging, a mosaic floor was discovered: it was located under

the street level, beneath a layer of 6,50 metres of burnt bricks and potsherd fragments; its size

was 7x10 meters.


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4 Construction works were immediately interrupted, in order to clear the floor from the

debris: the discovery was an unprecedented event for the city of Cologne: indeed, having

been inhabited uninterrupted for centuries, the most important Roman city in Germany had

surviving ancient buildings, but so far only discovered only in out-of-the-way suburban areas.

5 Until the construction of the bunker was being completed, that is towards the end of

1941, the mosaic was protected by a temporary shed; the floor was covered by a layer of dirt

and a concrete sheet, which was meant to save it from further damages, at least until the end

of the war.6 In 1946, at the end of the conflict, the mosaic was unearthed and in the month of October

of that year the discovery was made public. A corridor, dug all around the mosaic, allowed

visitors to observe the artifact closely, while the discovery was seen as a proper circumstance

for laying the foundations of the Rmisch-Germanisches Musem in Kln.

7 In the earlier days of the Roman Empire the use of mosaic in the Germanic provinces of

the roman empire was generally similar to that in the south. In this region black and white

mosaics and other pavement of Italian derivation had been introduced. However relatively,

little amount of examples survived. Here, the most productive and most characteristic period

began at the end of the second century and lasted until the German invasions in the area, in the

260s and 270s. Crowded ornamental compositions containing figured motifs and groups were

the most popular decoration of this kind of pavements. The range of subject-matter found onmosaics from this area is also characteristic: mythological scenes, scenes from literary life,

poets, philosophers and muses.3

8 The Dionysos mosaic decorated the triclinium of a rich roman domus and it is one of the finest

products of the Rhineland roman workshops: the field is covered with squares of guilloches

interlaced to form octagons; smaller squares are set on the points, while the spaces are filled in

with pairs of lozenges. Further, borders of meanders and dentils, outline these compartments.

Figures are placed in the octagons and squares, and the segments of these forms along the

edge. In total there are thirty-one panels in all. At the centre, a larger compartment is given

special emphasis by an additional guilloche border, and shows Dionysos leaning on a satyr;

all the rest contain Dionysiac figures and emblems of his cult. There is a contrast between

the richly ornamented framework and the lightness of the figured panels, were the figures

stand out against a plain ground whose white tesserae are set in an imbrication pattern. The

contrast extends to the colouring: bright, variegated tones, with considerable use of glass in

the figures and a more muted range in the frames. The figures themselves are classical in form,

well proportioned and carefully modelled. Despite controversy over the date, it is probably to

be placed in the later Severan period, around 220 AD.4

Technique and mosaic production

9 In order to investigate how to choose a correct setting bed for the detached mosaic, it became

relevant, to undestand antique technique and methods used by roman craftsmen and workshops

in general and to investigate, more precisely, wich materials were used in our case of study,

the Dionysos mosaic. Unfortunately, our knowledge is limited because ancient writers showedlittle interests in the activities of craftsmen and of manual workers in general; Vitruvius,

who wrote a book on architecture during the reign of Augustus is the only one who gives

detailled instructions for the construction of foundations of pavements. He starts with the

socalled statumen, a bedding of fist-sized stones, followed by the rudus, a mix of rubble and

lime and then the nucleus, or upper layer, a fine mortar mixed with three parts of crushed

tiles or potsherds5 These general stages he distinguishes are found in most mosaics throughout

the roman area; another very fine layer of mortar, the setting bed (object of our study) was

required for the actual laying of the tesserae, often composed by simple lime or lime mixed

with powdered potsherds which gave a rose colour to the mortar. Even if Vituvius never


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mentions this final layer, it was always found in all mosaics of roman and greek origin.6In

the case of the Dionysos mosaic, the only information we have, comes from the reports of

Fritz Fremersdorf, former director of the museum, who had the chance to observe the setting

bed layer of the mosaic before its stripping: he relates that the tesserae were laying on a pink

setting bed 2 to 4 cm thick.7

Our research

10 In 2007 the director of the Rmisch-Germanisches Museum asked the direction of the

ISCR for new advice; the result was a new cooperation agreement and the establishment of a

restoration campus operating throughout the month of July 2008.

11 During this intervention, a method was developed for the removal of the previous degraded

synthetic protection layer which had covered the mosaic for decades and had turned yellowish.

The yellow layer had modified the original colour of the mosaic subsequently altering the

right chromatic relationship between the tesserae and the interstices. In the light of new

and improved knowledge of the composition of the mosaics stratigraphy and the chromatic

relation between it and the tesserae, we judged it correct to replace the interstitial mortar with

a new and more appropriate one.8

12 In a mosaic of this size the percentage of surface occupied by the interstitial mortar is extremely

meaningful in the overall perception of the whole composition. At the end of the intervention

in Cologne, the replacement of the interstitial spaces with a material of a different chromatic

value has resulted in a significant variation in the chromatic perception ot the whole surface

(see ill. n.1).

13 This restoration gave the opportunity to put under scrutiny a subject so far not sufficiently

considered, i.e. the individuation of criteria underlying the choice of mortar in mosaics stripped

and relocated on new surfaces, and therefore deprived of their preparatory and layering strata.

14 The study began with an enquiry into the ancient executing techniques, relating to floor

mosaics. The question was the following: should the choice of interstitial mortar be guided

by our contemporary ideas of chromatic compatibility, or should we rather try to reproduce

the ancient execution techniques?9

15 Needless to say, part of the knowledge needed for a complete vision of all the factors to be

examined is far beyond a restorers or an historians reach, for it belongs to the general field of

physics and optics. The differences in the perception of colors depend on the physiology of the

eye and on the brains interpretation of visual stimuli and, more important, still they depend on

the mutual relationship between different colours, which is properly the focus of our enquiry.

Therefore, the research of those interactions plays the fundamental role of enlightening the

emerging chromatic combinations, which are responsible for unpredictable results.10

16 The study of the theory of colors has the practical and didactic goal to supply guidelines for

future restorations by showing the effects of different color juxtapositions11.

17 We organized an empirical check of the acquired results along two lines: we examined, in the

first place, the changes in the perception of the tesselated surfaces according to their features,

and then in connection with the influence of a chosen mortar.18 Then, we measured the variations which interstitial spaces undergo in consequence of a

stripping. It should be clear, from this short introduction, that the choices to operate in this

practice refer to work in fields that are often far from one another and that do not always admit

one solution. The possibility to reproduce ancient techniques, should it be feasible, would

free us from choices that might be considered arbitrary; lacking this possibility, it becomes

extremely important that one should have the availability of instruments capable to foster

decisions based on an adequate knowledge, and respectful of ancient materials.

19 In this perspective it is beyond our aim to suggest detailed univocal directions on the correct

methodologies, and even less to distinguish correct from incorrect solutions; our analysis tries


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to investigate, verify and tie together considerations about the choice of an interstitial mortar

and to examine the facts which affect their interaction.

Color perception in a museum environment20 The analysis of colours and their interaction has been a research field for centuries. It has

been a subject matter for physics, optics, and, more recently, neurology. However, as it was

ascertained, even a solid scientific ground is an insufficient basis for an explanation of their

interaction.21 The notion of harmony and contrast of colors is inherent in the very nature of mosaics, because

the final image is the outcome and effect of the juxtaposition of two basic chromatic units12.

These are, the tesserae and the interstitial mortar. Chromatic values depend from both the

constituent materials, and the manufacturing techniques.

22 The color in a mosaic is not, therefore, an intrinsic property of its materials; it depends

largely from the processing of those materials and the optical effects caused by the geometry

of the mosaic.

23 The study of chromatic relations among different tesserae is a virtually endless subject and

particularly interesting too, the study of execution techniques. In this paper we will only focus

on the chromatic connection between the tesserae and the interstitial mortar mainly from an

aestethic and visual point of view.24 As far as the study of museal restorations go, dimensions, constitutive materials, the color of

tesserae, with their texture, along with their setting bed, are a set of factors in mutual and

varying relation. In each restoration one has to cope with new circumstances, which call for

different choices.

The Experimentation25 Our experimentation has been prompted by the wish to investigate into the aesthetic fruition

of a mosaic artefact, as it is conditioned by different restoration practices. In our study we

have taken into account two aspects of restoration: we have valued, in the first place, how

the color of interstitial mortar affects the reading of the entire mosaic; subsequently we have

investigated the way in which the stripping of a mosaic may produce a variation in the ratio

between tesserae and interstice.

26 The stripping operations may cause variations in the spatial ratio concerning the interplay

of tesserae and interstices. We need to remember that our discussion is referred to mosaics

that were displaced from their original site and placed on a new setting bed and thus by this

operation being modified in their proportions and chromatic character.

27 In the evaluation of the chromatic element in a mosaic, lacking previous data and research,

along with every bit of interstitial mortar, the choice of materials must be well reasoned; it

must be also suggested by the mosaics uniqueness; which, in turn, is connected with the

quality of the original materials, the choice of techniques and the state of preservation of the

manufact. These elements must be considered, in different ways, as the starting point of any

new intervention.

28 The particular section of the Dionysos mosaic that we selected for our experiment isrepresentative of the colours appearing in the larger artifact, and particularly of the geometrical

frame enclosing the images, which has a capital role in the entire artifact.

29 Therefore, we made three identical copies of a section of the mosaic, which differed from one

another only in the colour of their interstitial mortar: our aim was to verify the extent to which

this affected the final perusal of the entire image.

The tests30 The choice of the materials for the tesserae was made in consideration of the need to use

colours similar to those of the original tesserae in the Dionysos mosaic. With this in our minds,


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we selected four types oftesserae: the white ones are in botticino marble, the black ones

in nero assoluto granite, the yellow ones in yellow travertine and the red ones in rupas

red marble (ill. 2). The three sections, each measurung 30 x 40 cm were placed on a Aerolam

basis through a tecnica direttathat consists in pushing the tesserae directly in the mortar.

Fig. 2 Samples of the modern tesserae used in our tests

The tesserae chosen for the test were made by stones different from the original ones for origin, but similar in colours.

Crdit: F. Moro

Test n.1 pink mortar

31 For the choice of the laying bed mortar, in test n. 1, we followed the information extracted from

accounts of the Dionysos mosaic in which the original laying bed was described as made of

mortar and potsherds powder. Therefore we used a mortar made of equal amounts of hydrated

lime and potsherds powder with the aim of reproducing, as closely as possibile, the visual

impact of the Dionysos mosaic before 1959, that is before its detachement, when the mortar

was removed along with the mosaic itself (ill. 3).13


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Fig. 3 Test n.1 potsherds powder setting bed

The tesserae are layed on a pink mortar, composed of lime and potsherds powder.

Crdit: F. Moro

Test n. 2 concrete

32 In our second test we intended to recreate the look of a mosaic laying on a concrete bedding

because this is the most frequent condition encountered when dealing with a detached

manufact. Almost all detached mosaics, as a matter of fact, are found today laying on a

concrete laying bed: this, of course, affects negatively the preservation of the tesserae, besides

provoking perceptive alterations connected with the chromatic nature of the mosaic itself. The

process of reconstruction is the same as in test n. 1: the laying bed is common grey concreteonly (ill. 4)


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Fig.4 Test n. 2 concrete setting bed

The tesserae are layed on a cement setting bed.

Crdit: F. Moro

Test n. 3 light white mortar

33 In our third test we decided to reproduce the effect of a mosaic laying on a traditional mortar,

made of a part of hydrated lime and a part of sand (very fine yellow sand and grey sand in

equal quantities; ill. 5).

Fig. 5 Test n.3 white mortar

The tesserae are layed on a white mortar setting bed composed by lime and yellow-gray sand.

Crdit: F. Moro


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Some considerations on the aesthetic carachteristics of thetests

34 In observing the three specimens we noticed that even in their small proportions the chromatic

variations were quite evident. The most relevant differences emerged from a comparison of

specimen n. 2 (layed on a concrete mortar) and mosaic n. 3 (layed on a white mortar). The

spectrum of reflectance of the three mortars, shows quite a clear difference between mortar

n. 2 and mortar n. 3; such a difference and can be also observed in the other tests. In the testusing a concrete laying bed the color of the tesserae appears saturated, while certain other

contrasts are visible, namely one between the grey-coloured concrete and the white tesserae.

In test n. 1, on the contrary, such a contrast seems softer and the transition from color to color

appears rather mild while every color looks unsaturated, despite the fact that identical tesserae

were used in the three different tests.

35 With regard to the disposition of the tesserae we came to the conclusion that, as was expected,

the nature of their arrangement appeared more evident in areas of higher contrast between their

color and that of the mortar: this was particularly evident in the case of test n. 2, but also in the

contrast of the blacktesserae against the background of the laying mortar in test n. 1 and n. 3.

Colorimetric measuring36 The variations observed at the end of our work regarding the perception of the mosaic, have

been measured with a test named image colorimetry with the purpose of quantifying

the color changes of the single tessera against the background of the laying mortar14. We

selected a set of tesserae for each of the four colours used in the tests; for each group the

l.a.b. coordinates were identified by calculating an average out of a rather large specimen of

tesserae. Subsequently we singled out in each test an area oftesserae representing every color

used: since each test was carried out using different laying mortars, each area was characterised

by three laying beds. In such areas an image colorimetry was carried out again in order to

find the l.a.b. coordinates of each area. At the end we obtained two different sets of results:

the first one concerning the absolute colour of each set oftesserae, the second concerning

the total effect of each set oftesserae in connection with each different interstice. From thecomparison of the two measurments we obtained the E with the aim of obtaining the effect

of the chromatic variation of the tesserae in connection with the different laying beds.


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Fig. 6 Graphic

The graphic shows the variation in perception of the colour of the tesserae laying on different setting beds.

37 From the results as shown in graphic in ill.6 we observe that the concrete laying bed and the

white laying bed produce fewer variations within the perception of the single tesserae. This

result was somehow expected since both mortars have an achromatic carachter, this property

in the end results in a very slight variation in the color perception of the tesserae themselves.

This in turn is owed essentially to a stronger impact of the laying bed on the brightness rather

then on the color tone of the mosaic.

38 We observed that the stronger variations are usually connected with the use of the pink mortar,

the only one which has a chromatic component.

39 This property of the mortar determines certain colour variations in all the sets of tesserae

we took as specimens, excluding the black ones. Indeed, as we know, achromatic coloursmodify the saturation data of a given colour; which concretely is perceived as a higher or lower

brightness but never in a variation of color. On the contrary, the justaposition of chromatic

colours (as in the case of the red tesserae on a pink mortar) determines a variation in colour

shade. We observed a similar effect in all our sets of tesserae which appear to be affected

in their colour in the first place by the pink mortar, then by the white mortar and finally, but

in a lesser way, by concrete. This effect is changed only in the case of blacktesserae on a

white mortar, in which the main variation does not pertain in the chromatic sphere but in the

sphere of brightness.

Virtual simulation

40 Our test proceeded with the use of virtual specimens similar to the preceeding lab tests withthe aim of enlarging the range of possibilities in the evaluations of the chromatic characters

in a reintegration. With this purpose in mind the virtual simulation was performed through

two distinct methods: a photographic and a graphic one. In the virtual simulation ofill. 7, the

choice of colours unusual ones in the sphere of reintegration- is ment to underscore if in a

extreme way the importance that such a fact has within the general perusal of such a manufact.

While being aware of the extreme nature of such a choice, never than less, we meant this as a

mere demonstration intending to show more clearly the question here discussed. In ill. 7 are

shown some of the meaningful cases.


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Fig. 7 Virtual simulation

This simulation of a mosaic laying on unusual colours shows relevant differences in perception of the colour of themosaic, depending on the laying bed colour.

Simulation F. Moro

41 We used the same technique to propose possibilities of reintegration on a photographic

detail of the Dionysos mosaic where the colour of the interstice (before restauration)

was substituted each time with different colours, thus offering a possibility for examining

chromatic reintegrations on the original manufact (ill. 8).

Fig. 8 Photographic simulation

This simulation of reintegration is meant to examine different possibilities of chromatic re-integration of the originalmanufact.

Simulation F. Moro

42 The graphic system of simulation, in turn, allowed us to analyse the way in which the level of

the interstitial mortar, in connection to the height of the tesserae, can modify the perception

of a mosaic if observed from different viewpoints.


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43 In the construction of virtual models we started, in this case too, from photographs of

laboratory tests: from these we obtained a 3D graphic reproduction in which we might vary

the height of the tesserae and that of the interstice (ill. 9).

Fig. 9 Virtual model

This model is constructed to show the variation in perception of a mosaic depending on mortar thickness.

Simulation F. Moro

44 The reintegration of interstitial mortar in the restauration of detached mosaics is usually aimed

at their preservation. We wish to emphasize the concept that, the first datum to keep in mind

in this operation depends on its state of the conservation. The level of interstitial mortar must

grant stability and permanence to the tesserae.45 From our experiment emerged that in the creation of the tests, the choice concerning the level

of mortar application: underneath or at the same level of the tesserae surface, generates a

different perception, when the eye is not perfectly perpendicular to the manufact.

46 In ill. n.10 we simulated a point of view of 45 for the mosaic in which the interstitial laying

mortar was set under its level on the right side and at the same level on the left side: one can

notice immediately that in this latter area the mortar and hence its colour will have a higher

relevance in the total composition.


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Fig. 10 Perception oftesserae

The perception of the tesserae depends largely on the colour chosen for the setting bed mortar.

Simulation F. Moro

47 Another fact which may cause different effects even when using the same mortar, is the state

of conservation of the tesserae: to the use of new ones with perfectly sharp borders follows a

regular texture of the manufact, in which the perception of full and empty spaces is balanced.

However in the area of mosaics from ancient floors the tesserae have usually worn corners

and edges, sometimes a consequence of the detachement procedures.

48 In this circumstances the laying out of an interstitial mortar on the same level as the tesserae

surface might unbalance the proportions.

The detachement of a mosaic

49 In order to verify the alterations undergone by a mosaic following to its detachment, we

decided to strip and successively replace the texture of one of the mosaics in a lab experiment

(ill. 11).


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Fig. 11: Lab test of mosaic detachment

The detachment test was made using traditional detachment techniques applied on a small dimension specimen, to

reproduce the stress suffered by a mosaic during a stripping procedure.Credit: Fabiana Moro

50 We focused our attention on the analysis of the size variations. These usually appear as

an enlargement of the interstitial space, thus provoking an alteration in the texture of the

mosaic, a fact which changes the perception of colours of the whole artifact. We measured the

consequent alterations through a hybrid monoscopic photogrammetry15.

51 We then recorded the images of our test before and after the detachment and subsequently, by

means of specific software, we measured the alteration which had occured in the test (ill. 12).


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Fig. 12 Variations of measures registered after the detachment of the mosaic.

The test showed in a small scale the damages that a mosaic undergoes during a detachment procedure.

Credit: Fabiana Moro52 As a result, and as was expected, the whole surface of the mosaic was enlarged, the size of such

a variation being proportional to the size of the manufact, in consideration to the dynamics

that such an experiment implies. For example, one element worth considering is the strenght

of the canvas used for the detachment: the weight of the tesserae and the strength used in

the detachment cannot be uniform on the whole surface; besides the pulling force to which

the canvas is subject is not easy to control in a large mosaic. In our case, a minor amount of

deformation, was connected with the small size of the manufact and therefore a higher control

on the whole procedure.


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53 The surface of our manufact did not undergo any significant changes in size; however, we

noticed certain significant deformations. The inner decoration showed the highest degree of

deformation, caused by the rolling of the mosaic on the tubular structure used for the stripping.

The same sort of deformation occurred in the entire manufact. We can therefore conclude that

the detachment had as a consequence a dishomogeneous variation in the size of the manufact,

and a change in its symmetry.

Conclusions54 Our work aimed at registering the elements involved in the choice of interstitial mortars inmosaics that were detached and re-layed on new support. In being removed from their original

support they suffered from double damage: in the first place their removal involved a loss of

information of their original support; in the second place, they suffered considerable damages,

connected with their stripping, the treatment they underwent and their replacement on a new

support.

55 We also investigated the elements to be considered in selecting the right mortar for the

reintegration and this because we believe that the primary needs in the treatment of a manufact

are its conservation, a correct philological investigation of its history and a right perusal of

a manufact itself. Beginning from these primary needs, a number of elements must be taken

into consideration; these, in turn belong in different areas which by their very nature cannot

be mastered by a single professional capability. One wonders then if such elements should be

considered one at a time or wether they are to be considered simultaneously. The nature of

restoration, in consideration of the materials involved, is a matter in which the working out of

a general protocol is not possible and which indeed implies each time a new elaboration and

the application of different methods.

56 Our research began with a philological hypothesis an approach might appear rather unusual-

however we believe on the strenght of our experience, that the interpretation of a manufact

and the study of its elements are the necessary premises in order to repropose its formal

appearance16.

57 In the case of mosaics, such an investigation is particularly important in as much as

an inadequate attention to philological questions has been responsible, in the past, for

considerable delays in the area of methods. Such a delay was considerable both on a theoretical

ground and in the practice of restoration: a faulty knowledge of ancient manufacts leads to

bad forms of conservation. We assume for instance, but it has not been the current practice to

do so, that it is possibile to preserve the original setting bed, and that a practice of mimetic

reconstruction and the substitution of the tesserae is not acceptable; even more important,

workshop tests demonstrated that preservation in situ is definitely possibile. Therefore, we

thought it might be useful to investigate into the relationship between restoration methods and

a philological perspective concerning the works in question, so that the original connection

between a manufact and its original context is understood in the most complete way- this is

our contribution in the founding of a conservative procedure upon a correct theoretical basis.

58 We believe it is most important to investigate into the kunstwollen (the wish for art) of

the author of a manufact, as we are persuaded that this might help in its restauration: in thisfield too, techniques must be guided as much as possible by philological principles when

conservation practices are deviced, and by the knowledge of ancient civilisations. Such an

investigation naturally has its limitations, as we tried to keep in mind and take into account

all along.

59 In this particular case, in considering interstitial spaces we tried to understand to what extent it

was possible to establish the relevance of such spaces. Indeed a mosaic should to be considered

as an organic system, in which interstices between tesserae are a relevant element, and not

simply a sort of net meant to add vibrations and charm to an image. Are they indeed a structural

element in the representation and a part of the manufacts history, with all its irreguralities and


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Notes

1 This article is a spinn-off of our degree research in Mosaic restoration, discussed on December 2009

at the Istituto Superiore di Conservazione e Restauro of Rome. The colorimetric measurements and the

photogrammetric testings were carried out by the Physics lab of the ISCR of Rome with the help of dott.

Fabio Aramini.

2 About the story of Dyonisos Mosaic see Fremersdorf 1956, p. 29; Dunbabin 1999, p. 82- 85; Parlasca

1963, p. 109-128.

3 See Dunbabin 1999, p. 79-91.

4 About the controverso on the datation see Dunbabin 1999, p. 81.

5 See Vitruvius, I , VII, ed. Corso 1997; Moore 1968, pp. 60-65. This composition would be diversified

according to the raw materials available in different aereas: in central Itlay, for example, rather than

rubble and pebbles, pozzolana sand was used as it was easy to find in that aerea and also because of

technical charachteristics of its hydraulicity. For the same hydraulicity necessities in other provinces of

the Roman empire such as Gemania and Northern Africa ones, the sand was substitued by brick powder

and potsherd fragments.

6 About the observation and study of this layer see Moore 1968, p. 60-65.

7 Fremersdorf 1956, p. 27; Doppelfeld 1962.

8 Ardovino 1994, p. 33-48; Ardovino 2002.


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9 Ardovino 2002.

10 Frova 2004; Gregory 1998.

11 See Goethe 1981.

12 Albers 2005, p. 21; Casagrande 2008, Frova 2004, Gregory 1998.

13 Fremersdorf, describing the mosaic in the digging report writes: Seine Steinchen sind in einen roten

Moertel eingebettet der, zwischen 2 cm (nach der mitte hin) und 4 cm (zum Rand hin) schwankt. This

information lets us presume that the mortar was composed by brick powder. See Fremersdorf 1956, p. 27.

14 See Palazzi 1995.15 See Fondelli 1992.

16 Vitruvius, ed Corso1997; Balmelle-Darmon 1983, Donderer 1989, Dunbabin 1978, Dunbabin 1999,

EAA 1967.

Pour citer cet article

Rfrence lectronique

Fabiana Moro et Angelica Pujia, The newly applied mortars in mosaic restoration , CeROArt[En

ligne], 6 | 2010, mis en ligne le 18 novembre 2010. URL : http://ceroart.revues.org/index1759.html

Fabiana MoroFabiana Moro graduated in Decorative Arts in 2003 from the Fine Arts Academy in Rome. In 2009

she obtained her second degree from the Istituto Superiore per la Conservazione e il Restauro in

Rome, specializing in the restoration of stone, stuccoes and mosaics. At the moment she works as a

restorer at Palazzo Barberini in Rome.

Angelica Pujia

Angelica Pujia obtained her Degree in Classical Archaeology from RomaTre University, in 2004. In

2009 she graduated from the Istituto Superiore per la Conservazione e il Restauro specializing in the

restoration of stone, mosaics and stuccoes. At the moment she is working at mosaic restorations in

Leptis Magna, Libya and Djemila in Algeria.

Droits d'auteur

Tous droits rservs

Rsum / Abstract

Lintervention de restauration sur la mosaque de Dionysos Cologne a permis, dans le cadre

du travail de fin dtude, une recherche sur les problmatiques lies au choix du lit de pose

des mosaques detaches et replaces sur de nouveaux supports. Elle a contribu ltude

des facteurs qui influencent la conservation des mosaques qui ont prcdemment fait lobjet

dinterventions de dtachement du site originel.

Mots cls : mortier interstitial,lit de pose,mosaque,restauration,mosaques dtaches

The restoration of the Dionysos mosaic in Cologne gave us the opportunity for analysing

the process involved in the choice of interstitial mortars in mosaics that were detached from

their original site and re-layed on new supports, thus losing their original setting bed. This

intervention lead us to investigate the relationships between restoration and a philological

perspective and the damages following the stripping of mosaics.

Keywords : laying-bed,interstitial mortar,detached mosaics,mosaic,restoration


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Idelson

moro, f. y pujia, a. newly mortars in mosaic restoration. 2010

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