Kirsten Trampedach

Introduction

Christianity was officially introduced to Danish society during the tenth century The first churches, of which there is only archaeological evidence today, were wooden constructions (1). During the twelfth, and especially the thirteenth century a great number of stone churches were built. The most frequent building materials were granite boulders or ashlars, but calcareous tufa and limestone were also used, though less frequently. In the middle of the twelfth century the knowledge of brick production reached Denmark, and from this time bricks became the preferred building material, not only for new constructions, but also for changes and additions to existing architecture. Today, the exteriors of churches either show the bare building material or are limewashed (2).

About 1700 medieval churches are preserved in Denmark. Stylistically, they can roughly be divided into two periods: the Romanesque – from the end of 11^th century to the end of the 13^th century, and the Gothic period – from the end of the 13^th century to about 1500. Basically, the Romanesque construction consisted of a flat-ceilinged nave and choir with small windows. Sometimes an apse was added to the choir at the east end and a tower to the nave at the west end. During the Gothic period churches went through major changes. Vaults were constructed, windows enlarged and chapels, vestries and towers were added.

All churches have probably been decorated with wall paintings (3). Today, visible paintings from the earliest period up to modern times are preserved in about 600 churches. Most of the decorations represent the Catholic period from the 11^th century to the mid 16^th century, when the Protestant Reformation was introduced in 1536 but protestant wall paintings are not uncommon.

The style of wall paintings can be divided in a similar way to the architecture: the Romanesque from the end of the 11^th century to the end of the 13^th century, followed by the Gothic period, which lasted until the Reformation. As we do not have any written sources about the creation of these paintings, we have to look at them in the context of European art. Accordingly, it seems that the wall paintings in Denmark, especially during the early Romanesque period, were, to a great extent, executed by painters from abroad, who were probably connected to monasteries. West European as well as Byzantine influence in style and iconography indicate international contacts, and often the quality of execution is extremely high and in keeping with other comparable works in Europe. The paintings in this period are figurative, and most frequently depict motives from the New Testament – often placed in regular framed friezes and painted on coloured backgrounds.

During the Gothic period the motives changed and included representations from a wide range of saints. Profane motives also became part of the world of Gothic images. During the early Gothic there seems still to be quite an international influence, but with time, the works seem gradually to become more regional and probably were painted by local artists. Visually, the paintings also undergo a change. They were painted on whitewash and the white background became an important artistic effect.

Painting techniques

While discussing the issue of painting technique of the Danish wall paintings, it is important to point out the fact that there are often quite big differences in the way painters were working, even within each century. However, a rough differentiation can be made between the techniques of Romanesque and Gothic wall paintings, though there is a continual development of our knowledge during each of these periods. Because there are no existing contemporary written sources dealing with the execution of Danish wall paintings, the knowledge gathered in this field is based on observations combined with scientific analysis.

Romanesque paintings

The preparation prior to the painting process consisted of measuring out the proportions and the placement of the particular elements of the composition. This process was followed by the sketching of the composition with incisions or outlines painted with a brush in red or yellow colour (4). Characteristic for the Romanesque wall paintings was the filling of the entire surface with colour. The basic colours were applied on a fresh plaster, which was specially prepared as a ground for the paintings. Sometimes a thin limewash was applied on the fresh plaster before the colours were applied. In that way, a fresco effect was obtained, which presumably was the intention of the painter. However, there is no evidence of works having been divided into giornate. The plaster was applied in horizontal courses (pontate) depending on the placement of the scaffolding and the joints of the pontate often pass through the figures. The final details and outlines were painted in secco, probably using lime or organic binders (5). However, not all paintings were executed on fresh plaster. We have several examples showing that the painter had used an already existing plaster as ground for his work, and in those cases the paintings must have been executed entirely in a secco technique. The colours in use were red and yellow ochres, ultramarine, azurite, copper greens (basic copper chlorides), cinnabar, red lead and carbon black. To those a white colour similar to lime white, know as San Giovanni white, can be added. In addition, gilded stucco haloes or other details in stucco are occasionally seen.

Gothic paintings

The changing of technique and materials is usually a gradual process, but, as the architectural structure changed radically with the constructions of vaults, the church spaces, as a consequence, became light and had large whitewashed surfaces. This had a strong influence on the style of the painting, which, as radically as the architecture, found new ways of expression.

Typical for the Gothic period was the application of a rather rough and thick layer of limewash, which formed the ground for the painting. As in the Romanesque period, the technique of Gothic paintings varies in the sense that sometimes the painter worked on a fresh limewash and in other cases on a dry ground. That means that also in this period paintings are found where colours were fixed during the process of carbonatisation, which might have the same effect as in the fresco technique, even though it is not comparable or identical with the classic interpretation of this term. But we also presume that either an organic binder or lime was added to pigments during this period.

The composition – both figurative and ornamental – was sketched in more or less detail before the basic colours were applied. In general, the preparatory phase was not as thorough as during the Romanesque period, but it was, nevertheless, necessary for the painter to position the figures and other elements on the vaults and walls before applying the colours. Most frequently, this was done with an outline in red ochre. Architectural decorations on fresh plaster, however, were often incised. The Gothic paintings were also completed with details and outlines (usually black) in secco. The palette of the painter differs a little from earlier periods. Ultramarine disappeared and cinnabar is rarely used. Azurite had probably been in use, but we only have very little evidence, as this colour has a tendency to change into a green basic copper chloride (6). A lead tin yellow appeared – although seldom – and mixtures of different pigments also seem to be more frequent (7).

History of conservation

Most medieval wall paintings were covered with limewash during the 18^th and 19^th centuries. The white church interior was in favour – partly as a result of a pietistic movement, but probably also because of a change in taste. But, despite the fact that many of the paintings had a Catholic content, they were tolerated after the Reformation in 1536, and were left visible for centuries to the people attending the church. The religious change did not lead to the systematic iconoclasm which happened in other parts of Europe. This is an important reason why there are about 600 churches with visible wall paintings today, and many more where the paintings are preserved behind layers of limewash.

The 19^th century's growing nationalist revival woke an interest in medieval wall paintings, and a great number of uncoverings took place from the middle of the century and onwards. The very first uncovering took place in 1826 in The Holy Three Kings'Chapel in Roskilde Cathedral (the Royal burial-place), but the actual restoration of the 15^th century wall paintings did not take place until 1855- 58.

The incitement to uncover mediaeval wall paintings in the 19^th century was, first of all, interest in the iconographic content of the paintings, but the artistic quality also played a role in decisions whether to preserve a painting or not. Due to the fact that the iconographic and aesthetic factors were of such importance, restoration was often limited to repainting, and, if necessary, reconstruction – not only in cases when smaller parts were missing, but also when motives were totally lost. This often led to misinterpretations. As the number of uncoverings increased, the reconstructions often were inspired by already known paintings from the same period. It is therefore often difficult or simply impossible to estimate the date of such paintings. The painting technique had little interest to early restorers, and hardly any effort was made to try to copy or imitate materials or methods. Lime was indeed often used as a binding medium, but animal glue and casein were also frequent.

Visual harmony was not necessarily obtained by a completely opaque overpaint. Also in this early period we find examples of restorations where there was a serious attempt to respect the state of preservation of the newly uncovered painting. One method was to impregnate the painted surface with water glass (alkali silicate solution) in order to make the painting appear brighter, and afterwards apply a glaze.

During the first half of the 20^th century attitudes to conservation gradually changed. The restoration of wall paintings became a profession, and it was recognised that this field demanded professional expertise. The augmentation became more scientific and restorations were often based on preliminary investigations. Still, repainting and reconstruction did take place, but the conservator did not take the liberty of doing it to such a wide extent as before. Much more attention was paid to the uncovering process, which earlier was often done by local people, who did not care too much about the results. Now, an important aspect was the preservation of what was handed down, and not the restoration of the object to its original form. For the first time one might say that preservation had priority over restoration. Documentation developed, and photographs were taken before and after restoration, although this was not a regular practice. The amount of written reports also increased, and even though the main issue dealt with was the iconography of the paintings, more and more information concerning the state of preservation was included. A detailed description of methods of conservation was still not part of the tradition of reporting, but such information occurred sporadically. In the second half of 20^th century the profession rapidly moved to a more academic approach. This, first of all, was due to the establishment of the School of Conservation at the Royal Academy of Fine Arts in Copenhagen, in 1973 (8). Here, the education of wall paintings conservators is still based on the fundamental approach of our predecessors in the profession: that lime is the basic material in the conservation and restoration of wall paintings, and that all interventions should, if possible, be reversible.

Conservation today

For conservators today it is important to preserve all facets of the painting, and in order to live up to that goal, some general principles are set out. The purpose is to preserve the authenticity of the painting as far as possible. However, conservators working with wall paintings in churches must submit to certain aesthetic demands from the church community, as the paintings are situated in a living environment where religious ceremonies take place, and, as such, cannot be compared to objects exhibited and protected in museums. Those circumstances often bring the conservator into a dilemma because of the contrast between antiquarian considerations and the expectations of the congregations. In practise, conservators today consider preventive conservation as paramount, and try to keep intervention to a minimum.

One of the most serious problems today is deterioration caused by salts (9) induced and increased by the installation of heating systems in churches, which began at the end of 19^th century. All Danish churches are heated today. Apart from salt transport, climate influences the degree of dirt deposits on surfaces. Conscious that the deterioration of wall paintings, according to our experience, is predominantly a surface phenomenon, and that deterioration escalates the moment paintings are exposed, we do not uncover wall paintings – unless a technical argument justifies this intervention (10). Such a technical reason could be the fact that the covering limewash layers physically cannot support the application of another layer, or that the paintings are covered with limewash to which an organic or synthetic binders was added (11).

The treatment of wall paintings is broadly divided between re-restorations of already exposed paintings (12) and restoration of newly uncovered decorations. As mentioned above, paintings restored during the 19^th century and to a great extent in the 20^th century are overpainted and reconstructed. Those paintings are considered to be historical documents of restoration, and, most often one decides to preserve the situation – so to say, to restore the restoration. This is done under the condition that the earlier applied methods are not harming the paintings. Another important issue is that the removal of overpaint/reconstructions in many cases also considerably diminished the narrative value of the paintings, leaving them as archaeological relics – a situation which in most cases is not acceptable to the congregation.

During the treatment of newly found paintings aesthetic intervention is limited to the amount necessary to "read" the damaged wall painting. Treatments are based on lime (13). Lime is used in different compositions and with different aggregates for consolidation, impregnation and retouching. But, of course, lime also has its limitations and other materials have been introduced, and new methods are developing continuously.

Cleaning methods are individually chosen depending on the state of preservation of the paint layer and the kind of dirt deposited on the surface. Dry cleaning, which is frequently done, is carried out with Wish-ab sponges (made of synthetic rubber) or "gomma pane" (14). Wet cleaning is carried out with water, with solutions of sodium bicarbonate, or under certain circumstances and with special care, with triammoniumcitrate. In the cleaning process, and also during other procedures, cyclododecane or menthol appear to be useful as a protection for paint layers and ground, prior to treatment. Impregnation with limewater has a long tradition in Denmark (15), and is still in use. Alternative methods with barium hydroxide have been successful, but both methods are only applied when necessary, and not as a general process in conservation.

Consolidation and repair of plaster and limewash layers are done with materials based on matured slaked lime, to which aggregates of different compositions are added. Quartz sand or powdered limestone are the most frequently used aggregates. If a lime material is not sufficient for fixing thin paint layers we sometimes have to use a synthetic adhesive, such as Primal AC33.

Retouching materials vary, but are always used in a way which distinguishes the retouch from original material. Dry pigments in limewater is a traditional method, and also watercolours were introduced in the second half of the 20^th century. In more recent years pastels have been used with success, as they are easily removable. As a principal, no reintegration is carried out on original ground, but if it is necessarily to improve the legibility of the painting, pastels are an appropriate choice. Plaster repairs without paint are often chosen as the aesthetic solution, especially for Romanesque paintings. Variations in the tone and hue of the plaster are obtained from the aggregate.

All restoration work is documented by a written, illustrated rapport. Photographic documentation before and after restoration is done by a professional photographer, while most photographs taken during the course of treatment are done by conservators. All records are stored in the archives of the National Museum and are publicly accessible. Computerised documentation has come into use, but doubts concerning the preservation of electronic data limit our trust in this way of archiving.

Organisation (16)

Danish churches are not protected by law, and the responsibility of looking after the buildings, wall paintings and inventory is put into the hands of a local, democratically elected parish council (17). The council is required to make a survey of the church every year, and a representative of the deanery is present every third year. All defects have to be reported, and the council has to have them repaired. The financial foundation for these repairs is a special tax paid by members of the church. Before a project is carried out it has to be presented to the local diocese. All changes and repairs of buildings or objects more than 100 years old have to be approved by the diocese. The approval is only confirmed after consulting with experts, among whom are experts employed by the National Museum. One of the many assignments carried out by the National Museum is the production of proposals for restoration of wall paintings. The actual restoration projects are usually done by conservators employed by the Conservation Department at the National Museum (18).

Conclusion

In spite of the fact that technology and knowledge about preservation of wall paintings have increased during the last half century, it is also a fact that wall paintings are more threatened than ever. Changes of the interior climate are among the most serious problems at the present time, and this problem will increase as the demand for comfort in the church interior is growing. For the moment, we do not have a practical solution to that problem, because a climate optimised for the survival of the paintings will not be acceptable to the congregation. An additional difficulty is the growing use of the church interior for other activities, such as concerts, theatre and other cultural initiatives, and this puts additional stress on wall paintings and other objects. What has been preserved for the past 1000 years is now in danger of being lost within a generation or two. If we do not find solutions through a dialog with the church authorities, our most important task as conservators will be the preservation of the paintings for the future by covering them up

again – as they were for a long period before their uncovering in the 19^th century!

Notes and References

1. Fragments of decorated plaster were found during an excavation in Lisbjerg church (near Aarhus) in 1997. The plaster had been applied to reeds on the wall of a wooden church.

2. Most of the limewashed churches are white, but red and yellow limewashes are also used in certain regions.

3. 'Danske Kalkmalerier' Vol 1-7 København 1986 - 1992

4. P. Bøllingtoft. 'Undersøgelser af metoder og materialer i romansk monumentalmaleri', Unpublished examination paper (1992) School of Conservation, Copenhagen.

P. Bøllingtoft. 'Untersuchungen von Massen,Massstabsvorlagen und Konstruktionsmethoden in den Monumentalmalereien der Kirchen von Idensen und Vä', in Forschungsprojekt Wandmalerei - Schäden. Hannover (1994) pp. 54-60.

5. The analysis of binding media has not been very conclusive to date. The organic products are deteriorated and very difficult to trace. The results are often polluted by other impurities, which can be misleading in the interpretation. In spite of this fact, the laboratory at the National Museum has obtained results which indicate that organic binders were in use.

I. Brajer and M.C. Christensen. 'The Restoration of Medieval Wall Paintings in Denmark – Ethics and Treatment Methods Based on the Case Story from Nibe Church', Zeitschrift für Kunsttechnologie und Konservierung 10 (1996) pp. 29-30.

6. Azurite was identified in the dress of Mary in Vindeby Church (the island of Lolland). The colour appeared green, as a major part of the pigment had turned into a basic copper chloride.

K.Trampedach. 'Sengotisk Kalkmaleri -analysemetoder og maleteknikker', Unpublished examination paper (1988). School of Conservation , Copenhagen, p.47-49 and 160.

7. A lead tin yellow was identified in wall paintings from the middle of the 15^th century in Kvislemark Church (Southern Zealand).

K. Trampedach. op. cit. p. 47-49 and 194.

8. The education leading to a Bachelor's Degree lasts 3 years, or 5 years to a Master's Degree.

9. Poul Klenz Larsen, Peder Bøllingtoft. 'Desalination of a Painted Brick Vault in Kirkerup Church' ICOM-CC Preprints (2000) pp. 473-477

Poul Klenz Larsen.'The Development and Testing of a Salt Extracting Mortar' International Journal for Restoration of Buildings and Monuments,Vol 7,No 1 (2001) pp79-90

10. 'Conservation for the future:The National Museum of Denmark's Counselling Service on wallpaintings in Denmark' in Forschungsprojekt Wandmalerei-Schäden Hannover (1994) pp 160-161

11. Organic or synthetic binders were often added to limewash during the 1960s, when it was difficult to buy a well slaked lime. Because of the poor quality of lime that was available, masons or painters were tempted to add other binders. In 1976 a mason, Michael Jørgensen, took the initiative to produce pit lime, thanks to which there is access to good materials today.

12. Kirsten Trampedach.'Early Restoration of Danish Wallpaintings and their Rerestoration' Les Anciennes Restaurations en Peinture Murale. SFIIC Dijon 25-27 Mars 1993 pp 131-141.

13. 'Lime-based Materials used in Conservation of Wallpaintings in Denmark' Studies and Conservation Experienece. Sighisoara, Romania (1995) pp 79-84

14. "Gomma Pane" is a mixture of flour, copper sulfate, sodiumcarbonate and water, which is baked before use.

15. Isabelle Brajer and Nicoline Kalsbeek. 'Limewater absorption and calcite crystal formation on a limewater-impregnated secco wall painting', Studies of Conservation 44 (1999) pp. 145-156.

1. Ulla Kjær,Karl Søndergaard Nielsen, Kirsten Trampedach. 'Nationalmuseet i Kirken' Nationalmuseets Arbejdsmark. København ( 1998) pp 167-183 (english summery pp 182-83)

18. The department of Conservation at the National Museum employs about 100 people. The department is subdivided into the following sections: Metal, Paper and Textiles, Paintings (on canvas, wood, polychrome sculptures and decorated interiors in profane buildings), Furniture, Wall Paintings, Organic Materials, Laboratory and Administration. The Section of Wall Paintings, which also includes stone conservation, employs nine conservators.