Heat and Light

Heat and Light: The Jerusalem Windows

Ivo Rauch

Jerusalem, as is well known, is a city that has a high symbolic value for many beliefs. It is a religious and political melting pot, but it is also a source of conflict between the great religions: Judaism, Christianity and Islam. The Lutheran Church of the Redeemer is located in the middle of this city, which is turbulent in many respects (fig. 1). Only 50 metres away is the Church of the Holy Sepulchre, whose complex building was erected over the legendary site of Christ’s tomb. The Wailing Wall, which is revered by the Jewish people, is only a few minutes’ walk away, close to the Al-Aqsa Mosque, the most important place for the Muslim community after Mecca. The Church of the Redeemer is also located directly on one of the most important pilgrimage routes in Christianity, the Via Dolorosa, which is traversed daily by thousands of pilgrims and tourists, who follow the path Jesus took on Good Friday. As we know, since the time of Constantine and later the Crusades, Jerusalem has been the scene of fierce battles for supremacy in these holy places. So how were a relatively late Christian denomination, the German Lutherans, able to build a church here?

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Jerusalem was almost forgotten as a pilgrimage destination for Europeans in the period after the Reformation. This only changed with the rise of revivalist movements in the first half of the nineteenth century. In particular, Crown Prince Friedrich Wilhelm Nikolaus of Prussia (later King Friedrich III.) oversaw much activity here. In 1869, the Sultan of the Ottoman Empire, Abdülaziz, gifted the eastern part of Muristan in the Old City of Jerusalem to the friendly Crown Prince. Friedrich commissioned the Berlin architect and architectural historian Friedrich Adler to plan the reconstruction of the Church of S. Maria Latina as the church of the newly founded Order of St. John. ¹ However, these plans did not come to fruition at first. It was not until the summer of 1883 that Otto Groth, the site manager of the Wittenberg Castle Church, arrived in Jerusalem and began his work, initially by clearing the building site and carrying out archaeological excavations. ² In 1893 the foundation stone was laid and on Reformation Day and in 1898 the church was consecrated in the presence of Kaiser Wilhelm II and the imperial family. The rising brickwork of the church was almost completely rebuilt and the building forms of the Church of the Redeemer must therefore be considered a new creation of the late-nineteenth century. Its principal form is based on the crusader churches of the twelfth century and was built on a cruciform ground plan in the basilica system. A circular main apse and two secondary apses close the nave and aisles to the east. The western façade was decorated (possibly at the personal request of Emperor Wilhelm II) in more modern Gothic style with a large rose window.

Originally, the interior was elaborately decorated with wall paintings and the apse mosaic with a bust of Christ, which is still present today.  Of the original windows installed when the Church of the Redeemer was built, only the three choir windows of the central apse and the small tympanum window above the northern entrance door have been preserved (e I, n II, s II; fig. 2). These windows show – entirely in keeping with the historicist style canon – Romanesque ornaments with palmette bands in the choir and vine leaf ornaments in the window above the side entrance door. According to archival sources, they were produced (together with the rest of the original glazing, which is now lost) at the Königliches Glasmalereiinstitut, Berlin-Charlottenburg, and completed in October 1897. According to the delivery contract, only the three main and two side choir windows, as well as the west rose, were filled with “rich musivic stained glass”, i.e. classical historicizing stained glass made of genuine antique glass. All other windows were glazed with unpainted “cathedral glass in lead”. ³

The present impression of the room is strongly influenced by the refurbishment of the church and the adjacent buildings in the years 1970-72 by the architect and retired states building officer Ernst W. Krueger from Berlin (fig. 3). ⁴ In addition to extensive alterations in the adjacent buildings, the church in particular was extensively redesigned. The interior was greatly altered following contemporary ideals of church design. Among other things, all wall paintings and wall plasters, with the exception of the Christ mosaic in the choir apse, were completely removed. Numerous stones were replaced, the organ and altar were rebuilt, the pulpit was moved and its sound cover was removed. Obviously, Krueger was anxious to bring the entire church together, to create a harmonious spatial impression in a contemporary style. To achieve this vision, he also changed the glazing of the church.

Already some years before, from 1966 onwards, a renewal of all the windows of the Church of the Redeemer had been considered as part of a general redevelopment. The architect responsible at the time, Langmaack from Hamburg, had met the Hamburg glass painter Klaus Moje in the Lutheran Church in Amman (Jordan) and asked him for drafts and a cost estimate for a renewal of the windows in Jerusalem. Moje supplied a sample design, showing rectangular panes in various shades of grey with blue bands inlaid, which has been preserved in the parish archives (fig. 4). ⁵ However, in his covering letter, Langmaack pointed out to Moje that this request was initially non-binding and that no funding was currently available for the work. In the end, no windows were made to this draft design, although it is still unclear whether the work was not undertaken due to lack of money, or whether it was prevented by the political circumstances and the Six-Day War in June 1967.

Only around 1970 was the subject of windows taken up again, now in connection with the finally imminent general renovation of the church. The aforementioned architect Ernst W. Krueger, who was now responsible for the refurbishment, reported that the late nineteenth-century windows extant at that date “are rusty and the glazing has been damaged by two wars in 1948 and 1967 and has only been repaired in a makeshift way”. The news of the forthcoming renovation of the Church of the Redeemer apparently got around quickly, as in October 1970 a young artist from Garmisch-Partenkirchen in Germany was already highly recommended to the planning architect by a business partner. The photo of a design sketch in the church archive shows the figure of an eclectic historicizing apostle Peter in the style of Dürer (fig. 5). However, this did not correspond with Krueger’s desired style. Friendly but determined, he made his vision clear: Dorfleitner’s (the artist) “conception of stained glass [seems] to be very much based on the historical, figurative style. Although I too appreciate this view, I don’t think it would be right for the windows of the Church of the Redeemer in Jerusalem. What we are trying to do here is a very light, not so colourful treatment of the upper windows using a few flat colour elements”. ⁶ With this, Krueger referred to the leitmotif of the planned new glazing. It should be light, not multi-coloured and work with large coloured areas. These, or similar descriptions can often be found in the correspondence around 1970 between the architect, the Jerusalem Foundation and the Provost of the Church of the Redeemer. An explanatory report for the Israeli administration emphasized this aim: “The church windows – especially those of the main nave – need repairing as mentioned before. For selecting the colour scheme, it has to be considered that the window areas themselves are not large and that the church – especially on dull days – is rather sparely lit. In order to improve on this, glass types have to be used which lead the light inwards, and in case of coloured glazing, this should be very light and bright”. ⁷

At the beginning of 1971 at the latest, contact was finally established with the Jerusalem-based artist Anna Andersch-Marcus. The building file kept in the archive of the Church contains the brochure of an exhibition of the artist in the Beit Tarbut (the House of Culture / בבית תרבות ) in Kfar Saba from early 1971, with a handwritten note of the opening hours. ⁸ Additionally, a newspaper clipping with a laudatory review of the artist and a typewritten list of references show the interest of the decision-makers of that time in the artistic work of Andersch-Marcus. The planning architect Ernst Krueger noted in a memorandum dated June 1, 1971, that the artistic design of the windows had been transferred to her, since “a review of her abilities with regard to formal and color design was positive and she could also demonstrate many years of experience in the design and supervision of glass work in Germany and Israel”. ⁹ Anna Andersch-Marcus’ innovative melting technique, with the help of which she was able to dispense with lead cames as a connecting element for the coloured glass, also pleased the Church commissioners, as this production technique could be carried out in Israel and was not dependent on expensive imports: “As lead glazing was expensive and not produced in the country [sic!], a different system was chosen, where coloured glass cut according to shapes was fired between two clear glass panes, a technique which allows high light transmission”. Anna Andersch-Marcus also recommended the executing workshop, Andreas Meyer Ltd. in Nahariya, which not only carried out the glass work but also the brass frames, “especially since it turned out that bazaar work in Jerusalem could not be carried out cheaper and not so true to size”.

The order to Andreas Meyer was placed in writing in June 1971, a month after Anna Andersch-Marcus had been commissioned to design and supervise the execution of the glazing. Andersch-Marcus was asked for:

• the production of the preliminary sketches in scale 1:10
• the cartoons in scale 1:1, i.e. the production of the templates
• the sending of the templates to the workshop
• the supervision of the production of the panels in Nahariya
• the supervision of the installation in Jerusalem.

 

As was to be expected, special emphasis was placed on the intended lighting effect, and this is specifically mentioned in the commissioning letter: “The glass surfaces are – in contrast to ordinary lead glass windows – to be kept so bright that in normal daylight the church is illuminated in such a way that it is possible to read in the pews without artificial light”. ¹⁰ All windows were then completed in the comparatively short time of six months, as the monthly report by architect Krueger for October 1971 notes: “All window frames, including the new glass windows, also in the apses, were delivered and installed on time” (fig. 6-9). It is remarkable that, throughout the entire drafting and negotiation process, the files give no indication of a religious theme for the windows. The main focus is on the lighting effect in the interior and the harmonious insertion of the coloured surfaces into the now bare stone walls, which following the renovation were left without plaster or a wash. It almost seems that the liturgical use of the windows – at least according to the files – did not play a particularly important role. The only mention of the window’s iconography, unfortunately without further proof, was made by Jürgen Krüger twenty years later, in his 1994 church guide: “The overarching theme is evolved from Psalm 130: ‘From the depths I call, Lord, to you. Lord, hear my voice’ (PS 130, 1-2). According to the artist, the hands raised in the side aisles are surrounded by the light of grace in the nave’s upper aisle, while the cupola tambour windows are entirely dedicated to the idea of Salvation”. ¹¹ To which statement by Anna Andersch-Marcus Krüger refers here remains unclear. Nevertheless, the windows of course have an obvious, coherent chromatic concept: while the windows in the side aisles and the side choirs are designed in blue and grey shades, with a few red accents, the colour palette in the upper aisle is dominated by yellow and white shades until finally the overall composition in the dome windows ends in sand and golden brown colour tones. All in all, the artist has succeeded extraordinarily well in fulfilling the client’s most urgent wish: she created a light and welcoming glazing scheme that blends harmoniously with the stone surface of the walls. The windows have a lasting effect on the atmosphere of the Church of the Redeemer and submerge architecture and visitors alike in a soft, calming – literally contemplative – light.

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When it was decided in 1971 to commission the designs for the new windows in the Church of the Redeemer from Anna Andersch-Marcus, who lived in Jerusalem on the Mount of Olives, this decision was probably made, as explained above, mainly for aesthetic-artistic reasons. It is a testimony to the professionalism and aesthetic standards of the decision-makers of the time that they gave priority to the professional qualities (at least according to the archival records) and that the remarkable biography of this artist was not mentioned.

Anna Andersch-Marcus was born as Anna Nagel in 1914 in Kiel (north Germany) and was the daughter of Anna Friederike Nagel née Peters from Kiel and Christian Henry Nagel, whose Jewish mother came from France. ¹² Her father was first Chief at the shipping company HAPAG and served as a frigate captain in the First World War. ¹³ After the war, the whole family moved to Mannheim, where her father worked as an engineer and she attended the Mannheim grammar school. In 1930, Anna moved to Kiel again and one year later began studying at the Kiel School of Applied Arts, where she studied graphics, writing and art history. When this school was closed in 1933, she moved to Berlin. In 1937 she married Adolf Kinau, the son of a famous North German novelist, Johann Wilhelm Kinau, better known under his artist name ‘Gorch Fock’. ¹⁴ Anna was in great danger because of her half-Jewish father and her liberal political activity during the National Socialism era. “Already in 1933 she took part in actions against the Nazis. Because of her refusal to join the Nazi Student Union and because of a speech on democracy, she was banned from studying and working in 1935. The SS confiscated 20 expressive woodcuts […] and destroyed them as ‘Bolshevik’ art”. ¹⁵

Anna Andersch-Marcus herself provided interesting information about this dangerous episode and her further activities during the Nazi period in a rare television interview around the year 2000. ¹⁶ After her husband was drafted, she moved to her parents-in-law’s house in Hamburg in September 1939. After her ‘rebellious’ Berlin activities became known, she was “put out on the street by the Kinau family […] with her children” and moved into a simple, basic flat in Finkenwerder. Nevertheless, Anna Andersch-Marcus seems to have been supported by the Kinau family even after the forced departure and also after the separation from her husband Adolf Kinau. In the following years she designed several front pages for the publications of her father-in-law Gorch Fock and for the publications of her brother-in-law Jakob Kinau (fig. 10). ¹⁷ These book designs are among the few surviving works by the artist from the wartime period, since most of them were either confiscated by the SS or destroyed in a fire in her picture store in 1943.  There is a legend that Anna owed her survival in Hamburg to the fishermen, “who protected her from attacks by passing her off as a crazy artist and tolerating her”. ¹⁸ Apart from this somewhat legendary sounding reasoning, perhaps her close connection with the Kinau family, highly respected in the Nazi period, also played a role, since the works of Gorch Fock, his brother Rudolf Kinau and especially his son Jakob Kinau were promoted by the regime and were always highly appreciated by the officials. ¹⁹ In financial terms, Anna Andersch-Marcus was able to survive despite being banned from her profession by secretly selling watercolours and by commissions for applied design, including some for Nazi organisations, which were given to her by artist friends and teachers.

Anna Andersch-Marcus was probably strongly influenced by Expressionism in this early, now lost, work. In her interview c.2000, she herself describes her woodcuts, destroyed by the SS in 1935, as ‘expressionist’ art. The surviving book illustrations from the Nazi period show her as an experienced illustrator who was able to impressively stage the desired theme (fig. 10). The books by Gorch Fock and the Kinau family were appreciated during this period for their drama, but also for their connection to the ideology of the German homeland. Accordingly, Andersch-Marcus designed the title pages sometimes in romantic, naïve-looking detail, as in the ‘Hamborger Janmooten’, sometimes in expressive tension as in ‘Seefahrt ist not’ or ‘Freibeuter’. All these designs have in common the sovereign handling of rather liberally designed colour spaces and especially the last two publications give an idea of the illustrator’s artistic home. Whereas in ‘Freibeuter’ diffuse colour surfaces are reflected in the water in an almost abstract way and also rise dramatically in the air as smoke, in ‘Seefahrt ist not’ Andersch-Marcus designed the ice blocks in which the little ship got stuck as splintered pictorial elements, graphically rendered as cubes and the trees and masts of the ships in the background as an accumulation of black hatching and jagged lines. Of course, these book illustrations are applied art, which in adaptation to the political and personal situation of the artist can only allude to the artist’s intention in a masked way. Nevertheless, they also show the sovereign, hidden abstract handling of forms and colours and the artist’s ability to deal with the given task on a high level.

After the war, Anna Andersch-Marcus took on several commissions for ‘Kunst am Bau’ in Hamburg and the immediate vicinity. In 1949, she married the graphic artist Martin Andersch and gave birth to her son, Dirk Andersch, in the following year. During this time, she came into contact with the literary “Gruppe 47” and studied art history in Hamburg again. She designed costumes, stage sets, and book covers and, for fourteen years from 1954, she was responsible for the design of the monthly Esso petrol magazine. Of course, in this context, special attention should be paid to her work on the design of glass windows (fig. 11). According to Anna Andersch-Marcus herself, she came to this genre of art rather by coincidence: “It was like this: I hadn’t been working there very long when Mr. Ostermeyer came and said, oh, listen, make me a church window. I can’t, I told him, I’ve never done one. He said you can, make me a church window. All right, I did the church window up in Borgfelde”.

A detailed study of this artistic œuvre is, unfortunately, still pending. It is to be expected that many of these windows have been lost or have been heavily altered. In 2005, for example, the Heiligengeist Church in Barmbek was demolished for the construction of new apartments and only a few remnants of the windows found their way into a Protestant Community Centre in Hamburg. ²⁰ Windows designed by Anna Andersch-Marcus in Norderstedt were also in danger of being destroyed when the Church was converted into a kindergarten in 1974. Fortunately, the windows were saved from a skip, stored and in 1976 they were relocated to the Vicelin Church, albeit with parts missing. In 2001, the local church community organized an exhibition of paintings by Anna Andersch-Marcus and a fundraising campaign to complete and restore the cycle of paintings depicting the ‘Foolish Virgins’. ²¹ These windows in Barmbek and Norderstedt are technically traditional stained-glass windows, in which coloured antique glass was cut according to the cartoon and assembled with lead cames. Historical photos show Anna Andersch-Marcus working on the templates for cutting the glass and selecting the glass. It can therefore be assumed that she was closely involved in the practical execution of the windows, or even undertook some elements of the glazing process herself. As already mentioned, around 1958 the artist then turned to the technique of fused glass, with which she created a wall design in the school on Sengelmannstrasse in Hamburg. This technique certainly suited her style, which often juxtaposed large areas of colour with sharp edges. In her gouaches and watercolours, these colours were usually very softly modelled and tinted in pastel shades. This colour effect was also much easier to achieve by using ceramic colours in the above-mentioned enamel technique than by using strikingly evenly tinted antique glass.

Anna Andersch-Marcus later described her work attitude after the war: “We were so alive, as one can hardly imagine. We worked like horses, we were filled with the optimism that was after the war and with what we wanted to do”. ²² She commented on the painting process of a now lost painting named ‘Bright Sounds’: “It was a picture with golden brown tones and two white, completely abstract birds fluttering there, not just wings, but somehow a kind of flirtation”. ²³ She now avoided figurative painting and often dealt with bright areas of colour in geometric fields. Many landscape paintings have been handed down from her (fig. 12). As Maike Bruhns has observed, “She prefered sharp lines and contours; her landscapes and cityscapes grow out of themselves and have a tectonic character”. ²⁴ Bruhns quite rightly refers to the connections of Andersch-Marcus’ art with the landscapes of Marc Chagall and the even closer relationship with the colour field paintings of Lyonel Feininger. Here, both her origins in German Expressionism and the strong influences of Cubist painting are evident. After travelling to Anatolia and the Middle East in the 1960s, Anna decided to live in Israel in 1969; she converted to Judaism, the religion of her Grandmother, and married the philosopher Shlomo Marcus in 1970. Anna Andersch-Marcus initially had her apartment and studio on the Mount of Olives in Jerusalem, until she and her husband moved to Jerocham ( ירוחם ) on the edge of the Negev desert in 1988. ²⁵ She died there in 2005 and was buried on the Mount of Olives in Jerusalem.

Having introduced the artist responsible for the 1971 scheme, we can now return to consider the glazing of the Church of the Redeemer in Jerusalem as a whole. How should the value of this ensemble be assessed?  What criteria can be used to develop reasonable statements of its significance? Based on the above research and physical examination of the windows, various statements can be made about the significance of different elements of the glazing scheme.

The nineteenth-century windows (fig. 2), especially the main choir windows, are the only surviving remnants of the original glazing of this prestigious Wilhelminian building in the Holy Land. Through their colourfulness and ornamental presentation, the original polychrome appearance of the historicistic overall design can still be guessed at. If we assess this example using the framework developed by English Heritage (now Historic England) for identifying the significance of historic buildings, we can confirm the windows’ high aesthetic and historical values. ²⁶ Therefore, these panels must be preserved in situ.

The windows by Anna Andersch-Marcus (fig. 6-9) must be considered in the context of the 1971 refurbishment of the church as a ‘Gesamtkunstwerk’ of the modernist period, in their variety and finely tuned correspondence with the architecture in terms of colour and brightness. They reveal the designer’s artistic roots in Expressionism and Cubism of the first half of the twentieth century. Moreover, they testify to the commissioners’ courage to make a contemporary artistic statement, instead of choosing the alternative designs with retrospective figurative stained glass or handcrafted rectangular panes. The artist herself not only knew how to adhere to the specifications of the decision-makers (brightly coloured windows as accents in an otherwise stone-faced church), but also gave the building a soft, contemplative atmosphere of light, through the calm juxtaposition of tinted coloured areas. Furthermore, her panes of glass, manufactured using the glass fusing technique, must be regarded as very early examples of this design technique.

From a historical point of view, it is also extremely remarkable that, in 1971, the decision was made to award the contract for the window design in the Lutheran Church of Jerusalem to a Jewish artist; one who was at home in both Christian and Jewish tradition, who had survived the horrors of the Nazi regime and who, through her windows, had set an unobtrusive and calm sign of religious tolerance and political reconciliation, especially in such a turbulent and symbolically charged place as Jerusalem. From this point of view, it seems, therefore, essential to preserve Anna Andersch-Marcus’ windows in the place for which they were created – in the Church of the Redeemer in Jerusalem.

Having established their significance, let us now consider how the material technique and condition of these windows has affected the options for their treatment and future preservation. As early as 1958, Anna Andersch-Marcus had experimented with a technique that was to become important for the windows in Jerusalem in 1971. For a wall design in a school in Hamburg, “she looked for a glazier and together with him produced a huge drop of water […] in a technique that she would later repeat often. They cut panes into the desired shapes, dyed and fired them and then fired them together with two clear panes in the middle. With this sandwich process, lead as a connecting element between the individual discs is superfluous”. ²⁷ Anna Andersch-Marcus was one of the first artists to work on a monumental scale with this technique, which became known as ‘glass fusing’ in the 1980s. ²⁸ Even at the time of the production of the Jerusalem windows, this Fusing technique must still be regarded as very innovative. The artist used only white, uncoloured window glass as raw material for the Jerusalem windows, which was painted with ceramic enamel paints fired to the glass. This ‘coloured glass’ was then cut into the desired shapes, placed between two window-sized float glass panes and then melted together in the glass kiln. This melting of a ‘stack of glass’ was later called ‘stack fusing’, as these techniques were developed further. While modern stack fusing is achieved at temperatures around 1350°-1375° C, it can be assumed that the workshop of Andreas Meyer in Naharia worked at lower temperatures, because the glass edges are not fused, soft and round, but still have a right-angled cutting edge. There are also a comparatively higher number of air bubbles within the pane package and the panes are apparently not connected across their entire surface. One can see the cutline of the painted glass pieces, as well as hollow areas, very well in Fig. 13, taken from the outside through the clear white glass ‘sandwich’. These large hollow spaces, as well as the air bubbles and the irregular, blurred application of the enamel paint, are probably one of the artistic means of expression of these windows, which in their overall appearance are reminiscent of illuminated watercolours or gouaches. The fused glass plates, about 8 mm thick, were installed from the inside and are fixed with putty in brass frames specially made by the Meyer workshop in Nahariya.

Sadly, the windows of Anna Andersch-Marcus show heavy defects. Therefore, the question was raised whether to remove the windows completely and to replace them with new, artistically designed stained glass. However, this is not an option, due to the significance of the scheme. All of the windows are heavily soiled by dust, soot and cobwebs. The putty between the glass and brass frames is brittle and partly porous. The glass surfaces are not corroded or scratched. Even the enamel paintings, which are protected in the glass package, show no damage.

The main damage phenomenon in these windows is the presence of numerous cracks in the glass plates, which can be observed in almost all windows, albeit to a slightly lesser extent on the north side (fig. 13, 14). These glass cracks usually only affect the outer sheet of the glass package, but there are also various cracks that can be observed through all three sheets of glass.

The morphology of the crack patterns indicates that these are undoubtedly thermal cracks. ²⁹ Such cracks occur when significant temperature differences occur within one single glass surface; for example, due to the presence of radiators or sharp shading in strong sunlight. The so-called temperature gradient strength of ordinary float glass is only about 40 K. ³⁰ Consistent measurements of the glass surface temperatures in Jerusalem on window s II have shown that, even in December, the surface temperatures of the glass vary between 11° C at night and 54° C in the late morning, depending on the position of the sun and shading. Such values are recorded almost daily and, at 43 K difference, exceed the thermal load limits of float glass, even at a comparatively cool time of year. It is to be assumed that the temperature difference in summer is likely to be much greater. Some of these cracks apparently occurred as early as the year after the completion of the windows, as documented in a handwritten, unsigned note by the architect Krueger (?), dated 1972. ³¹ The Federal Institute for material testing in Berlin had been contacted in relation to this matter, and in a conversation with the glass expert there, Mr. Dipl.-Ing. Wagner, Krüger was informed that “The cracks in some of the outer panes of 3-part welded glass” are due to “Sunlight that only partially hits the window by heating the coloured central pane, which also reflects”.

In these circumstances, what kind of conservation concept may be appropriate? The windows by Anna Andersch-Marcus are of great value in terms of their artistic design, their influence on the spatial effect of the Church of the Redeemer and its historical background. It is therefore highly recommended that the windows be preserved in situ. Since the windows were made using a comparatively new technique, there is little experience, specific conservation techniques or standards that could be applied to this project. It is therefore highly recommended that any measures be first tested and evaluated on a sample window. As mentioned, the first cracks had already appeared in the windows in 1972. Although the number of cracks has certainly increased since then, none of the windows has so far become so damaged that pieces of glass have fallen out, and when the windows were examined, no glass was found to be loose or in danger of falling out. This shows the relative stability and ‘damage tolerance’ of this system. Often, only one pane of the glass package is cracked, so that the remaining layers stabilize the cracked glass. Even in the case of cracks that run through the entire thickness of the pane, the panes are not loose or in immediate danger of dislodging.

In theory, it would be conceivable to bond the cracks with suitable conservation adhesives, such as epoxy resin. However, the adhesive material would leak uncontrollably into the cavities and bubbles within the glazing and thus cover large areas of the internal glass surfaces. This is problematic in view of the climatic situation, as epoxy resin adhesives are very sensitive to UV radiation and can yellow and become brittle very quickly. Their use in this instance is therefore not recommended. Similarly, laminating the existing glass with additional panes from the outside, and/or inside, would not be effective solution, as such a measure would also require light-ageing adhesives. Moreover, lamination would make the glass packages very heavy, which would have to be compensated for by new fixings in the masonry.

Therefore, the implementation of a preventive conservation solution seems to be the best method available now to preserve these valuable windows. In the case of preventive conservation, interventions are limited to an absolute minimum. The focus of such a concept is to prevent future damage by securing fragile parts and by protecting the work of art from harmful environmental conditions.

Appropriate cleaning and stabilisation of the glass and support structure should be undertaken, to address the soiling of the windows and degradation of the putty which secures it within the frames. It should be possible to clean the windows from both sides in their current, installed state. This cleaning should be carried out using proven conservation techniques to prevent cleaning agents, or external soiling, from being washed into the cracks and cavities of the glass packages. Possible cleaning methods should be tested on a sample window to select the most appropriate approach. Glass cracks should always be left untreated. Only in the case of glass that is imminently at risk of becoming dislodged is it appropriate to secure such pieces of glass with a conservation-grade adhesive; as noted above, no instances of glass in this state have been observed so far during the examination of the windows.  The cementing between glass plates and brass frames must be checked. Loose putty chamfers are to be removed and refinished. Finally, all putty surfaces are to be professionally coated with a colour-matched paint.

To prevent further heat damage, all windows shall be equipped with sun protection on the outside. IR filter glasses, should be fixed, using clamps, into the external window reveals; it is essential to ensure that a circumferential ventilation slot is maintained. It is to be expected that the space between the historic glass and the protective IR glass, will become dirty over time, as it is ventilated from the outside. It will have to be cleaned at certain intervals. Different types of IR filter glass must be sampled in advance, as such glasses reflect light to varying degrees and the visual impact and thermal effectiveness must be tested on site. Fortunately, the windows of the Church of the Redeemer are hardly visible from the outside. Due to the dense building development around the church, only a few roof terraces in the immediate vicinity are afforded occasional views of the exterior of the windows. For this reason, the aesthetic impact of reflective thermal shielding panes on the church architecture is unlikely to be significant. Nevertheless, such an intervention must of course be sampled and carefully considered.

Additionally, since the possibility cannot be completely excluded that pieces of glass could come loose from the pane compound in future, a safety barrier must be installed between the windows and the pews, to prevent glass from falling and injuring visitors. This could be done relatively inconspicuously, by means of narrow strips of laminated safety glass with ground and polished edges, mounted on the window sills. This would sufficiently guarantee visitor safety.

In summary, the proposed combination of cleaning and preventive conservation should make Anna Andersch-Marcus’ coloured glazing more visible and attractive again. Furthermore, this approach should increase the longevity of these remarkable windows under Jerusalem’s specific climatic conditions. However, it must be pointed out that these windows are technically experimental designs from 1971, which require continuous monitoring and may have to be maintained at regular intervals.

References

1. For the architectural history compare i.a. Jürgen Krüger, Evangelische Erlöserkirche Jerusalem, Regensburg 1997; Jürgen Krüger, Die Erlöserkirche – eine protestantische Gedächtniskirche?, in Dem Erlöser der Welt zur Ehre. Festschrift zum hundertjährigen Jubiläum der Einweihung der evangelischen Erlöserkirche in Jerusalem, ed. Karl-Heinz Ronecker , Leipzig 1998, p. 163-183; for the history of the church community: Uwe Roland Protestantismus in Jerusalem. Die Erlöserkirche als Fokus einer gemeinsamen Geschichte, Berlin 2014.[↩]
2. The inherently complicated archaeological background of the building site is not subject of these observations. See instead: Ute Wagner-Lux / Karel J. H. Vriezen, Die Entwicklungsgeschichte des Ortes, auf dem Erlöserkirche erbaut wurde, in Dem Erlöser der Welt zur Ehre. Festschrift zum hundertjährigen Jubiläum der Einweihung der evangelischen Erlöserkirche in Jerusalem, ed. Karl-Heinz Ronecker , Leipzig 1998, p. 4-16 and Klaus Bieberstein, Sancta Maria Latina, Ein Erbe, das verpflichtet, ibd. p. 17-36.[↩]
3. See a handwritten copy of the contract by architect F. Adler from 01.07.1897, Archive of the Church of the Redeemer. On the famous Königliche Glasmalerei-Institut see: Angela Nickel, Das Königliche Glasmalerei-Institut (1843-1905), in Berlinische Monatsschrift 2 (1993), p. 8-16; Frank Martin, Das Königliche Glasmalerei-Institut in Berlin-Charlottenburg (1843-1905), in Das Münster 2 (2009), p. 100-110.[↩]
4. Before his retirement, Ernst W. Krüger was a head government building surveyor in the Department for Foreign Affairs of the Federal Construction Department, as he himself noted in a speech in July 1970. See typescript in the Archive of the Church of the Redeemer; concerning the building work in general see Krüger, Evangelische Erlöserkirche, p. 12.[↩]
5. Langmaack to Moje on 09.03.1966, letter, Archive Church of the Redeemer.[↩]
6. Krueger to Prochaska, 15.11.1970, letter, Archive Church of the Redeemer.[↩]
7. Krueger, “Explanatory Report”, 15.02.1970, Archive Church of the Redeemer.[↩]
8. Jerusalem, Church of the Redeemer, archive: Ernst Kueger, “concerning the production of new stained-glass windows incl. bronze frame for the church – note” from 1.6.1971.[↩]
9. Krueger’s handwritten memo dated June 15, 1974, Archive of the Church of the Redeemer.[↩]
10. Commission to Anna Andersch-Marcus, 01.05.1971, Archive of the Church of the Redeemer.[↩]
11. Krüger, Evangelische Erlöserkirche, p. 14.[↩]
12. Cf. Ralph Busch, „Auch nach Finkenwerder habe er sich nicht getraut.“ Anmerkungen zum Novemberpogrom 1938 auf Hamburgs „Elbinsel“ Finkenwerder, in Liskor – Erinnern. Magazin der Hamburger Gesellschaft für jüdische Genealogie e.V., May 2017, p. 21-36, p. 24.[↩]
13. See Maike Bruhns, Kunst in der Krise, vol. 2, Künstlerlexikon Hamburg 1933-1945, Hamburg 2001, p. 36-39, especially p. 36.[↩]
14. See the biography of this influential author: Rüdiger Schütt, Seefahrt ist not! Gorch Fock – Die Biographie, Darmstadt 2016.[↩]
15. Bruhns, Kunst in der Krise, p. 37.[↩]
16. Cf. „Hitler und die Frauen in der Kunst“, TV documentary from Thomas Hauser, co-production BR, MDR und ORF, 2002, First broadcast: 14.11.2002 in the BR.[↩]
17. See the remarkable contribution by Rüdiger Schütt, Zwischen Heimatbewegung und Moderne. Wer illustrierte Gorch Focks Bücher?, in Mythos, Marke, Mensch. Gorch Fock. Aufsätze zu Leben, Werk und Wirkung des Schriftstellers Johann Kinau (1880-1916) ed. Rüdiger Schütt, Nordhausen 2010, p. 127-154.[↩]
18. Bruhns, Kunst in der Krise, p. 37 and Busch, Finkenwerder, p. 25.[↩]
19. Especially Jakob Kinau in particular manipulated the original texts in the new edition of the books of his father Gorch Fock in the spirit of the ‚chauvinistisch-nationalen Grundlagen im faschistischen Deutschland‘, see Schütt, Heimatbewegung, p. 137 and Schütt, Seefahrt, p. 176. Significantly, some of Jakob Kinau’s works were classified as fascistic by the Soviet military government after the war. See Schütt, Heimatbewegung, p. 137.[↩]
20. Concerning the demolition of the church, see: ‘Wer rettet die Fenster der Heiliggeistkirche?’ in Hamburger Abendblatt, 25.02.2005; about the reuse of some panels: ‘Wo es unter dem Pflaster swingt’, in https://www.kirche-hamburg.de/nachrichten/details/wo-es-unter-dem-pflaster-swingt.html; accessed on 09.12.2019.[↩]
21. See ‘Der Zerfall der Jungfrauen’, in: Hamburger Abendblatt, 27.08.2001. The missing parts were not redesigned until 2013 by the Hamburg glass studio Hempel. See ‘Neue Glaskunst im Kirchensaal der Vicelin-Kirche’, in Hamburger Abendblatt 01.11.2013.[↩]
22. Andersch-Marcus, quoted after Beate Reimers, Anna Andersch-Marcus. Wüste und Wasser, Hamburg 1994, p. 6.[↩]
23. Andersch-Marcus, quoted after Reimers, Anna Andersch-Marcus, p. 11.[↩]
24. Bruhns, Kunst in der Krise, p. 38.[↩]
25. According to Reimers, Anna Andersch-Marcus, p. 12, the couple initially lived in Jerusalem “as a demonstration of the possibility of fruitful coexistence” among the Arab population on the Mount of Olives. “But arson and physical attacks put an end to this utopia. Since then the couple has lived in Yeruham in the Negev” (Reimers, Anna Andersch-Marcus, p. 16).[↩]
26. See: https://historicengland.org.uk/advice/caring-for-heritage/places-of-worship/making-changes-to-your-place-of-worship/principles-for-making-changes/assessing-significance/ (accessed 15.04.2020).[↩]
27. Reimers, Anna Andersch-Marcus, 1994, p. 9.[↩]
28. A technical or art historical survey of this glass decoration technique has not yet been written. Even if the knowledge of fusing glass layers together had been widespread since the invention of glass in Egypt and Mesopotamia, it was only in the 1960s in the USA that it slowly became popular to fuse large sheets together as artistic window glazing. See for the moment: https://en.wikipedia.org/wiki/Glass_fusing (accessed on 12.12.2019).[↩]
29. For detailed information on the causes of glass cracks see Ekkehard Wagner, Glasschäden. Oberflächenbeschädigungen, Glasbrüche in Theorie und Praxis, Stuttgart 2012; on thermal fractures in particular pp. 175-189.[↩]
30. This range applies to window glass as used in Jerusalem. In principle, this value can be considerably increased by technical measures such as edge finishing, thermal toughening of the panes (production of toughened glass) or higher quality glass formulas in the melt.[↩]
31. E.W. Krueger (?), unsigned handwritten memo dated 1.2.1971 in the archive of the Church of the Redeemer.[↩]