Visualizing the Fort
AN INVESTIGATION INTO THE USE OF 3D MODELLING FOR THE CONSERVATION AND RESTORATION OF A FORT OF THE DEFENCE LINE OF AMSTERDAM
Emma Egberts 11956771 MA Conservation and Restoration of Cultural Heritage, University of Amsterdam Specialization: Historic Interiors Supervisor: M. N. (Merel) van Schrojenstein Lantman, MA Date: 21-08-2020 Word count: 17.777
Summary
In this thesis, the use of 3D modelling technology for the conservation and restoration of cultural heritage has been investigated. This has been done specifically by studying the advantages and disadvantages of the use of the modelling program Blender for the case study of Fort benoorden Spaarndam. This is a military fort dating from the beginning of the 20th century and is part of the Defence Line of Amsterdam. In this fort, multiple wall paintings and decorative painting schemes have been found under layers of white overpaint. The decorations in room 23 have been investigated through architectural paint research, showing that five different decorative paint schemes have been present over time. These paintings are being threatened by two factors: the bad climate conditions in the fort, resulting in deterioration of the paint layers and the, still unknown, plans for the future function of the fort. It has been found that 3D modelling technology can create useful opportunities to deal with these problems, by documenting the current state of the fort, visualizing and reconstructing the historic phases and by disseminating these to a public in an immersive or interactive way. For the use of 3d modelling for conservation and restoration of historic interiors, Blender has advantages and disadvantages compared to other 3D modelling techniques. The disadvantages are that it is not directly based on recordings of reality, resulting in a less accurate model, or a model that can not be seen as an exact documentation of reality. The use of laser scanners or structured light scanners are a better option for this, for example to study the surface of a painting in high detail or to survey the condition of a building over time. These techniques are still relatively expensive and require the need of a skilled professional. Photogrammetry is, compared to laser scanning, a more affordable alternative, making use of photography, but does not record surface texture. The advantages of Blender however are its relatively easy use and the fact that it is available on the internet for free, making it a great option for projects with limited financial options and people with little experience in digital modelling. Next to this, it gives the modeler complete control, which is useful for creating a model that shows exactly what you want to show, making additions or reconstructing things that do not exist anymore.
Abstract In this thesis, the use of 3D modelling technology for the conservation and restoration of historic interiors has been investigated. This has been done specifically by studying the advantages and disadvantages of the use of the modelling program Blender for the case study of Fort benoorden Spaarndam, compared to other modelling technologies.
Abstract (Dutch) In deze scriptie is het gebruik van 3D-technologie voor conservering en restauratie van historische binnenruimten onderzocht. Hierbij is specifiek gekeken naar de voor- en nadelen van het modeleer programma Blender voor de case study van Fort benoorden Spaarndam in vergelijking met andere 3D-modelleer technieken.
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Inhoud Summary ...... 1 Abstract ...... 1 Abstract (Dutch) ...... 1 Introduction ...... 4 Chapter 1: Fort benoorden Spaarndam ...... 5 1.1 Metadata ...... 5 1.2 Fort benoorden Spaarndam ...... 5 1.3 Defence Line of Amsterdam ...... 8 1.4 Decorations ...... 10 1.5 Condition, conservation and restoration issues ...... 13 1.6 Other forts with wall paintings ...... 16 Chapter 2: Future fort ...... 23 2.1 New functions for forts within the Defence Line ...... 23 2.2 Involved parties ...... 23 2.3 Preservation of the wall paintings ...... 24 Chapter 3: Architectural paint research in room 23 ...... 26 3.1 Introduction room 23 ...... 26 3.2 Research techniques ...... 28 3.3 Results of sample analysis ...... 29 3.4 Results of stratigraphies ...... 33 3.5 Dating of the layers ...... 36 Chapter 4: 3D modelling technology ...... 40 4.1 Laser-scanning ...... 40 4.2 Structured Light Scanning...... 41 4.3 Photogrammetry ...... 42 4.4 3D modelling programs ...... 43 Chapter 5: Modelling process in Blender ...... 44 ...... 47 Chapter 6: Possibilities 3D models ...... 47 6.1 Documentation ...... 48 Visualization ...... 55 Dissemination ...... 59 Chapter 7: Limitations ...... 62 7.1 Limitations of 3D models ...... 62 7.2 Principles and guidelines ...... 64
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Conclusions ...... 65 Acknowledgements ...... 66 Bibliography ...... 67 Appendix 1. Room 23
Appendix 2. Overview decorations room 23
Appendix 3. Overview Stratigraphies
Appendix 4. Samples locations
Appendix 5. Sample Analysis
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Introduction
3D modelling technology has been used within the field of cultural heritage for multiple decades and is becoming more and more popular. However, professionals working the area of conservation and restoration of historic interiors have been more hesitant to use this technology, possibly because it is often thought to be expensive, difficult or not adding enough value. However, different techniques to create 3D models are available, with their own price range, use and results. One cheap and accessible way is the use of Blender, a free online-accessible modelling program in which a 3D model can be created without the need for expensive equipment.
In this thesis, the use of 3D technology for the field of historic interiors will be investigated. This is done by discussing the advantages and disadvantages of different modeling technology and comparing the use of Blender to these. A case study will be used to test the usefulness of Blender for the field of historic interiors. The case study that is being used is Fort benoorden Spaarndam (also called Fort Benoorden throughout this thesis). This is a military fort dating from the beginning of the 20th century that is part of the UNESCO protected world heritage Defence Line of Amsterdam. Within this fort, many wall paintings and painted decorative schemes have been found under layers of white overpaint. However, the preservation of these wall paintings is being threatened by two factors: the bad climate conditions in the fort and possible changes to the function of the fort. In this thesis it will be discussed how 3D models can be a great addition when dealing with these problems, by documenting and ‘preserving’ the paintings in in a digital way.
First, Fort benoorden Spaarndam and the conservational issues will be introduced. Then, the architectural paint research carried out will be discussed. After this, the different available 3D technologies will be explained, after which the creation of a 3D model of Fort Benoorden in Blender will be discussed. The use of Blender will be discussed by focusing on three areas that are important for the conservation and restoration of historic interiors: documentation, visualization and dissemination. The advantages and disadvantages of Blender for these areas will be compared to the other available 3D technologies, namely photogrammetry, laser scanning and structured light scanning. Through examples of other projects in which 3D models have been used, the possibilities for Fort benoorden Spaarndam will be highlighted. After this, the limitations of 3D models in general will be discussed shortly. Finally, some final thoughts and recommendations for future research will be discussed.
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Chapter 1: Fort benoorden Spaarndam
1.1 Metadata Name: Fort benoorden Spaarndam Address: Visserseinde, 2063 JD Spaarndam Part of: Stelling van Amsterdam (Defence Line of Amsterdam) Protected provincial monument Noord-Holland
1.2 Fort benoorden Spaarndam
Fort benoorden Spaarndam is a fort located in the Westbroekerpolder in Spaarndam, near Haarlem and forms the Position of Spaarndam together with Fort bezuiden Spaarndam. It has been built around 1885 and 1901 and could hold up to 299 soldiers and around 20 higher ranked officers. More men could be housed in the smaller buildings surrounding the fort, the ‘bergloods’ (destroyed by fire in 1924) and the ‘troepenloods’.1 The forts were designed to be small and low, to fit within the landscape, making it harder to target them. Earlier forts were built with bricks, but for the Defence Line of Amsterdam the then new material concrete was used. The fort building is classified as a Type A, a type of fort used between 1897-1907.2 This type consists of two buildings, a front building and a main building which are connected through a long hallway (called the Poterne). The front building usually has seven rooms for the guarding unit and a storage for munition, while the main building was used as the living spaces and storage rooms. Located here were the rooms for the soldiers with bunk beds, the more luxurious rooms for the higher officers and the common rooms such as the kitchen and hospital. These rooms are all similarly shaped: a rectangle with a vaulted ceiling and four doors leading to the next rooms. The east wall contains a door to the outside and two deep window-niches. The longer north and south walls also have wooden beams that have been built in the wall, which have been used to connect shelving to the wall or create a division in the room.
1 “Fort benoorden Spaarndam”, Stelling-Amsterdam, accessed 01-07-2020, http://www.stelling- amsterdam.nl/forten/spaarndam-noord/ 2 Fort types, Stelling-Amsterdam, accessed 03-07-2020, http://www.stelling- amsterdam.nl/stelling/extra/fortmodel/index.php#BOMVRIJ-A 5
Figure 1 Fort benoorden Spaarndam, back side. Photo: author.
Figure 2 Fort Type A, Source: https://www.stellingvanamsterdam.nl/nl/historie/stelling-van- amsterdam
Figure 3 Fort benoorden Spaarndam. Source: RCE
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Figure 4 Layout Fort benoorden Spaarndam. Source: Z. Ziegelaar
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1.3 Defence Line of Amsterdam Fort benoorden Spaarndam is part of the big network of military buildings that form the Defence Line of Amsterdam. This system was built between 1880 and 1918, as a way of defending Amsterdam based on an inundation mechanism, creating the possibility of flooding an area of land between 3 and 5 kilometers wide. The Defence Line is comprised of thirty-six forts, two coastal forts, two fortresses, four batteries and two coastal batteries.3 The Defense Line of Amsterdam was not the first defense mechanism based on inundation in the Netherlands, the Position of Den Helder (started around 1574), the Dutch Waterline (started 1672) and the New Dutch Waterline (from 1815 on) are earlier examples. Because of increasing threat from neighboring countries during the French-Prussian war of 1870-1871, a Defense Line around Amsterdam was created. This version was still very basic and minimal. On April 8th of 1874, the Fortress Law was passed, giving way to the development and modernization of the Defense Line.4
Figure 5 The Defence Line of Amsterdam. Source: https://www.stellingvanamsterdam.nl/nl/historie/stelling-van-amsterdam
3 “Introduction”, Stelling-Amsterdam, accessed 01-07-2020, http://www.stelling- amsterdam.nl/english/common/introduction/index.php. 4 “Defenisve Lines”, Stelling-Amsterdam, accessed 21-08-2020, http://www.stelling- amsterdam.nl/english/lines/netherlands/index.php. 8
Most of the forts were unoccupied during peacetime, except for the two coastal forts of IJmuiden and Pampus. When the First World War started, only some parts of the Defence Line had been completed but in 1920 the build was finished. In many cases, additions were made to the forts during the First World War. The mobilization for the First World War started on the 31st of July, 1914 and by the 2nd of August all forces were stationed at the forts. In total around ten thousand soldiers were based in the forts. Most of the forts stayed occupied until the end of the war in 1918.5 During the Interbellum, some forts were used as a prison for punished soldiers or conscientious objectors. At the start of the Second World War, however, many forts quickly became occupied by the Germans. The German army invaded the Netherlands on 10 May 1940 and the Dutch capitulation was already declared before the Germans had reached the Defence Line. The German occupiers also made additions and changes to the forts. After the war ended, some of the forts were once again used as prisons, such as Fort Spijkerboor.6 From the 1950s on most of the forts were used as a place to store munition or as a workplace to dismantle old munition. The advantages of the system of inundation and the need for a permanent defence mechanism diminished after the war and the forts officially lost their status as defence mechanism between 1956 and 1960. 7
As mentioned above, Fort benoorden Spaarndam was first in use during World War I. It is known that the third battalion of the Second Regiment ‘Vesting’-artillery (2.R.V.) was based in the fort during the First World War and shortly after and also parts of the 7th Regiment Infantery are thought to have been stationed at the fort during the first World War.8 More is known about the occupation of the fort during the Second World War. Dutch soldiers were stationed here at the beginning of the Second World War. Some signatures are left on a door, dated 17 May 1940, when a few Dutch soldiers were still stationed at the fort after the capitulation of 14 May while waiting for further instructions.9 Sometime after that, the fort became occupied by German troops.10 Sources mostly mention occupation by German troops in 1944, but because of the early date of the capitulation it can be expected that the
5 “Tijdlijn 1914-1945”, Stelling-Amsterdam, accessed 01-07-2020, https://www.stellingvanamsterdam.nl/nl/historie/tijdlijn-van-de-stelling-van-amsterdam/1914-1945. 6 “Fort Spijkerboor”, Stelling-Amsterdam, accessed 01-07-2020, http://www.stelling- amsterdam.nl/forten/spijkerboor/ 7 “Tijdlijn 1945-1960”, Stelling-Amsterdam, accessed 01-07-2020, https://www.stellingvanamsterdam.nl/nl/historie/tijdlijn-van-de-stelling-van-amsterdam/1945-1960 8 ”Fort benoorden Spaarndam”, Stelling-Amsterdam, accessed 01-07-2020, http://www.stelling- amsterdam.nl/forten/spaarndam-noord/ 9 J.A.T. Wijnen and Nico van der Woude, Muurschilderingen en Decoraties in Fort benoorden Spaarndam. Nulmeting, waardering, plan voor behoud (Wageningen: Wijnen Cultuurhistorisch Onderzoek, 2015), 36. 10 Wijnen, Muurschilderingen en Decoraties, 12. 9 fort was occupied by the German troops earlier than 1944. The first known mention of German groups is by resistance group Groep Albrecht, that mentions the presence of around 300 men on June 12, 1944, with a sign saying ‘Wassowsky’. This can be interpreted as a reference to the Fallschirm Ersatz- und Ausbildungs-Regiment Hermann Göring (part of Batallion Wossowsky) , which was a group of young soldiers training for the Luftwaffe. A day later, the resistance group mentions men from Luftwaffe troops, possibly from this group.11 These men left before July 2nd 1944 and were replaced by 100 (and later up to 300) SS- soldiers. On August 3rd, Group Albrecht mentions 200-250 men of the 6th compagnie SS (Polizei Division). All German troops are thought to have left around August 25, 1944.12 From the 1950s on, the Defence Line was being dismantled and Fort Benoorden lost its function as a defence building in 1951. After that, it was used as a storage space for munition of the navy, but from the 1970s on it was mostly empty.13
Figure 6 Table with the phases of use of Fort benoorden Spaarndam. Source: Jobbe Wijnen ...
1.4 Decorations In the fort, many wall paintings and painted decorations have been discovered under layers of white overpaint. Different researchers were brought in to investigate the fort’s history and the condition of these wall paintings. In 2007, research was done by Beek & Kooiman Cultuurhistorie together with Bureau M&DM. This research focused on documenting the fort and the paintings that had been discovered so far.14 In 2009 Stichting Krayenhoff commissioned three conservators to look into the condition of the paintings and necessary
11 “Fallschirm Ersatz- und Ausbildungs-Regiment Hermann Göring”, Katwijk in Oorlog, accessed 01- 07-2020, http://katwijkinoorlog.nl/fallschirm-ersatz-und-ausbildungs-regiment-hermann-goring/ 12 Wijnen, Muurschilderingen en Decoraties, 12. 13 Wijnen, Muurschilderingen en Decoraties, 10. 14 Mattie, Erik and Marijke Beek. Cultuurhistorisch Vooronderzoek. Fort Benoorden Spaarndam, (Amsterdam: Beek & Kooiman Cultuurhistorie, M&DM), 2007. 10 conservation treatment.15 More recently, research into the condition of the paintings and the conservational needs of the fort is continued by Jobbe Wijnen and Nico van der Woude. 16 Their research focuses on the history of the building in general and the different decorations that have been found, creating an indexation of the decorations present and a value assessment of the different decorations and rooms.17 However it is likely that there is still a lot that has not been discovered yet or that has been lost (either in the past or during the uncovering). This categorization consists of 7 categories:18 1. Functional paintwork: room names and numbers 2. Decorative paintwork: wainscoting, stenciled borders 3. Figurative paintings and drawings: artistic expression, made by hand. Different themes: military, rural/farmer, women, cartoons 4. Slogans 5. German slogans, drawings and paintings: different decorations linked to the German occupation 6. Signatures 7. Miscellaneous/modern graffiti
Some rooms contain a lot of the different decorations, while some contain only one or two. The decorative stencil work can be found in most of the rooms but are mostly all different in pattern and colors. The slogans can be found in three different rooms, carried out in a big size on the walls, in a colored and placed in a decorative framework. In three of the rooms drawings and slogans have been found that can be linked to the German occupation of the fort. These contain SS-signs, but also drawings with German texts and signatures. Other decorations could also be from the time of the German occupation but cannot be connected to this phase for certain. Signatures of people have been found in different locations in the fort. Some of them have been dated, showing the signatures are from different phases of the use of the fort. Most of the signatures date from people from the navy who were in the fort in the 1950s, however also signatures from 1940 have been found. Finally, a lot of modern graffiti is visible throughout the fort. These have been made with modern materials and are of low artistic and
15 Crèvecoeur, R., P. Dijkman, P & C. Junge. Behoud schilderingen in fort benoorden Spaarndam (brief aan de Stichting Krayenhoff), 2009. 16 J.A.T. Wijnen and Nico van der Woude. Muurschilderingen en Decoraties in Fort benoorden Spaarndam. Nulmeting, waardering, plan voor behoud. (Wageningen: Wijnen Cultuurhistorisch Onderzoek, 2015). 17 J.A.T. Wijnen and Nico van der Woude. Muurschilderingen en Decoraties in Fort benoorden Spaarndam. Nulmeting, waardering, plan voor behoud. (Wageningen: Wijnen Cultuurhistorisch Onderzoek, 2015). 18 Wijnen, Muurschilderingen en Decoraties, 20. 11 historical value but give an insight into the loss of function of the fort and its slow decay over the last decades of the twentieth century.
Figure 7 painting in the Poterne. Photo: author.
Figure 8 Decorations in room 4. Photo: author
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Figure 9 stenciled decoration. Photo: author
1.5 Condition, conservation and restoration issues Research into the condition of the fort has been carried out by Nico van der Woude in 2015.19 The condition of the building in general is relatively bad. Due to loss of function, the building has been neglected and not maintained, resulting in degradation of the building. People entering the building illegally has resulted in graffiti on many walls throughout the fort (see fig. 10). However, the biggest influence on the degradation has been due to climate, mostly because of moisture. The temperature and the relative humidity have been measured in different rooms over a few months. This has shown the relative humidity to be very high, fluctuating between 67,1% and 91,5%.20 This has resulted in the biggest moisture problems in the spring, when the temperature within the building is still low but the warm outside air contains a lot of water. When this air enters the building, for examples when doors or windows are opened, this creates condensation on the cold walls inside the fort, resulting in water damage to the walls and the paintings. Next to that, damages to the roof and clogging of the iron water-drains in the walls has resulted in rainwater entering the building, causing
19 N. van der Woude, Fort benoorden Spaarndam. Onderzoek naar conditie en conservaring van de schilderingen. (Stichting Restauratie Atelier Limburg), 2015. 20 N. van der Woude, Fort benoorden Spaarndam. Onderzoek naar conditie en conservaring van de schilderingen. (Stichting Restauratie Atelier Limburg, 2015), 2. 13 more water damage throughout the fort. In the winter, the water has frozen and caused cracking in the walls. Dripping of water is visible on the walls, where it has resulted in discoloration and transfer of dirt and salts (fig. 11-14). The moisture in the walls also results in the efflorescence of salts. In the wooden elements of the fort, the moisture has led to the formation of fungi and overall degradation of the wood. The moist conditions have also had a big effect on the wall paintings. The paint used on the walls is a chalk-based paint, which is hygroscopic and very susceptible to water. Because of this, the paint layers have become moist and powdery in many places, due to decreasing binding power of the binding medium. In other places the paint layers have become very rigid and dense, probably because of chemical changes from material used in the concrete walls. Next to this, the transfer of salts has and the cracks in the walls have resulted in delamination of the paint layers in many places, resulting in a disturbed surface and a disturbed experience of the decorative painting schemes (fig. 15). Additionally, there is a lot of discoloration visible on the most recent painting scheme, probably resulting from water damage and transfer of dirt. The leaks in the roof have been fixed, removing a big source of the water damage, but the shifts in relative humidity and condensation in the spring still form a damaging factor. Besides climatological damage, the fort was filled with moths and spiders. Most of these have been removed. The moths are likely to return if the conditions in the fort are not changed. Finally, the wall paintings have been uncovered to some extent. However, it proved very difficult to completely uncover the paintings without loss of paint. Next to that, in most cases also a haze would stay visible on top of the uncovered painting because of it being difficult to completely remove the overpaint. Removing the layers of overpaint often results in quite a lot of damage to the paintings, impossible to remove the overpaint without damaging the paintings to some extent. Currently visible in the room is a disturbed experience of the room, due to the degradation of the fort in general, dirt accumulation, discoloration and paint loss. However, also the visibility of multiple decorative paint schemes within the walls causes a disturbed image. The wall paintings are visible in combination with the most recent painting phase. This shows a wrong representation of the paintings. Instead they should be experienced within the coherent decorative framework in which they have historically been visible. To ensure the conservation of the fort in general and the wall paintings more specifically, the indoor climate conditions should be stabilized to decrease damage to the paint layers. Next to this, the currently sensitive paintings should be consolidated, but more research into this is needed. Besides consolidating and stabilizing the climate, the future function of the fort is another important factor for the conservation of the paintings. A function for a historic building is often needed to create financial options for maintaining the building
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and creating interest and valuation for its safeguarding. This could result in a public function with a connection to the history of the building such as a museum, in a more private function when used by a company or business or in a combination of public and private functions. The use of 3D models can be a useful addition for most of the different scenarios for the future of the fort, as will be discussed in chapter 6.
Figure 10 Graffiti-artist 'Joel' in room 29.
Figure 12 Water damage in Fort Benoorden. Source: Jobbe Wijnen Figure 11 Water damage in Fort Benoorden. Source: Jobbe Wijnen
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Figure 14 Salt and surface dirt on paintings in room 15. Source: Jobbe Figure 13 Deterioration of the paintings. Room 23. Source: Author Wijnen
Figure 15 White haze and discoloration. Source: Jobbe Figure 16 Paint flaking off in room 23. Source: Author Wijnen
1.6 Other forts with wall paintings
The wall paintings at Fort benoorden Spaarndam are not a stand-alone example. The fort is unique in the fact that it contains many wall paintings that seem to date from different periods of use of the fort, but a few other forts of the Defence Line are also known to have wall paintings. However, documentation and research is not available for most of these forts, showing the need for a better documentational framework collecting research into multiple forts in one location. The use of decorations and artistic or individual expressions are thought to have been more common in forts and military buildings, ranging from organized projects to graffiti, even though little research has been done on this topic.21
21 Military graffiti has been described in: 16
At Fort bij Nigtevecht, now used as meeting rooms and a café, two soldiers are said to have painted scenes from the life of the soldiers in the canteen between 1914 and 1918. 22 However, no evidence of these paintings could be found, except for it being mentioned in text.23 In Fort bij IJmuiden, opened to the public once a month, a few wall paintings dating from the German occupation during the Second World War have been found (see fig. 17 and 18).24 These wall paintings have suffered mostly from vandalism and paint loss.
Figure 17 Paintings at Fort bij IJmuiden. Source: festungsbauten http://www.festungsbauten.de/NL/Amsterdam_Ijmuiden.htm
Figure 18 Paintings at Fort bij IJmuiden. Source: festingbauten. http://www.festungsbauten.de/NL/Amsterdam_Ijmuiden.htm
Jobbe Wijnen, "'Vermaas, la vache qui rit'. Militaire graffiti als bron voor archeologisch en historisch onderzoek naar alledaagse militaire cultuur," Tijdschrift voor geschiedenis 131, no. 1 (2018): 143-154. Kenny Brouwers, “The Walls as a Silent Witness to it All: a Preliminary Introduction to Conflict Related Graffiti,” Kunsthistorisch Tijdschrift Desipientia 21, no. 2 (2014): 24-28. 22 “Fort bij Nigtevecht”, Stelling-Amsterdam, accessed 21-08-2020, http://www.stelling- amsterdam.nl/forten/nigtevecht/index.php. No images were found. 23 “Soldaat Meijer”, Stelling-Amsterdam, accessed 21-08-2020, http://www.stelling- amsterdam.nl/mensen/overig/eerste-wereldoorlog/index.php#MEIJER. 24 Timeline of the Defence Line of Amsterdam, 1914-1945, Stelling van Amsterdam, accessed 21-08-2020. https://www.stellingvanamsterdam.nl/nl/historie/tijdlijn-van-de-stelling- van-amsterdam/1914-1945. 17
Another fort containing wall paintings is the other fort of the Position of Spaarndam, Fort bezuiden Spaarndam. These paintings are copies of paintings from the Rijksmuseum, such as ‘Sinterklaasavond’ by Jan Steen (see fig. 19-21). Their artistic quality is higher than the paintings from Fort Benoorden, but they are in relatively bad condition.25 It is unknown from what time these paintings date. Another interesting example from this fort is the painting of a
landscape above an embrasure. This landscape would have mirrored the landscape that is visible through the opening, helping the soldiers aim in foggy weather. Historic images of the fort show that stenciled borders have been present here as well (fig. 22.) The walls had at some point been painted in yellow with a black painted plinth, but besides this very little is known about the decorative paintwork in this fort. Fort Bezuiden Spaarndam has been developed into a multifunctional location, with a café, small museum about the Defence Line and a small exhibition room. It also offers options for renting boats and organizing events.26
Figure 19 Close-up of painting at Fort bezuiden Spaarndam. Source: tripadvisor
Figure 20 Wall paintings in Fort bezuiden Spaarndam. Source: Author
Figure 21 Wall paintings in the café at Fort bezuiden Spaarndam. Source: author
25 Mattie and Beek, Cultuurhistorisch Vooronderzoek, 19.
26 “Fort Zuid”, Forten.nl, accessed 21-08-2020, https://forten.nl/forten/fort-zuid/. 18
Figure 22 Copy of photo showing stenciled decorations in Fort bezuiden Spaarndam. Source: author.
Another fort from the Defence Line that contains figurative paintwork is Fort bij Spijkerboor. During the Second World War it was used as a detention center for soldiers and after the war for war related criminals.27 The wall paintings in the Poterne are thought to have been made by one of the prisoners around 1945-1946.28 They are visible together with a yellow-blue wall. Next to that, there is also a small decorated chapel in the fort (fig. 23 and 24).29 The fort has been restored and the paintings are presented in a museum-like setting, with a protective covering and spotlights. This fort is also open for visitors on a limited basis.
27 “Fort bij Spijkerboor”, Stelling van Amsterdam, accessed 21-08-2020, https: //www.stellingvanamsterdam.nl/nl/fort-bij-spijkerboor. 28 “Fort bij Spijkerboor”, Stelling-Amsterdam, accessed 21-08-2020, http://www.stelling- amsterdam.nl/forten/spijkerboor/index.php. 29 “Fort bij Spijkerboor”, Oneindig Noordholland, accessed 21-08-2020, https://onh.nl/verhaal/fort-bij- spijkerboor-1. 19
Figure 23 Paintings at Fort Spijkerboor. Source: rondomkijken.nl
Figure 24 Paintings in the Poterne at Fort Spijkerboor. Source: rondomkijken.nl
Figure 235 Paintings at Fort Spijkerboor. Source: festungbauten.de
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Next to the figurative paintings found in these forts, a similar example of stencil decorations has been discovered in Fort aan den Ham. No research into this discovery has been published, but pictures posted on the website of the fort show an uncovered part of the wall with traces of the stenciling decorations in two rooms, of the higher ranked officers and fort commander, which has been replicated on the other walls of these rooms (fig. 26 and 27).30 This fort has been restored to some extend as well, with a reconstruction of the rooms of the higher ranked officials and the hospital room. Other parts of the fort are in use as exhibition rooms for a military museum.31 Stencil decorations are also said to have been found in the room for the officers at Fort bij Krommeniedijk, but these have not been documented and are currently not visible.32
Figure 26 Stenciled decorations at Fort aan den Ham. Source: rondomkijken.nl
30 Blogpost 2 January 2013, Fort aan den Ham, accessed 21-08-2020, https://www.fortaandenham.nl/cms/blog/page/6/.
31 Fort aan den Ham, accessed 21-08-2020, https://www.fortaandenham.nl/cms/. 32 Fort bij Krommeniedijk, Stelling-Amsterdam, accessed 21-08-2020. http://www.stelling- amsterdam.nl/forten/krommeniedijk/index.php. 21
Figure 27 Screenshot from video of Fort aan den Ham. Room of the fort commander with stencilled decorations. Source: https://www.fortaandenham.nl/cms/fort-rondleiding/
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Chapter 2: Future fort
2.1 New functions for forts within the Defence Line After the forts of the Defence Line lost their function from the1950s onwards, a small number has gotten a new function.33 Some have been given a museum function, offering tours, exhibitions and events related to the history of the fort or the Defence Line, such as Fort Pampus and Fort bij Krommeniedijk.34 Other forts are opened to the public on a more limited scale. Fort bij Edam has limited access for visitors, keeping the fort relatively unaltered since the 1980s.35 Next to forts keeping their link to the history of the Defence Line, some forts have been given a more commercial destination, such as locations for events, restaurants or exhibitions. For example, Fort aan de Nekkerweg has been changed into Fort Resort Beemster, a spa resort.36 However, the majority of the forts of the Defence Line has not been opened to the public.
2.2 Involved parties The complex of the buildings of the Position of Spaarndam has already been a provincial monument since 1990 and in 1996 the Defense Line of Amsterdam as a whole has been recognized as World Heritage by UNESCO. 37 However, in practice this mostly means protection of the structure of the Defence Line, not specifically protection for the interiors of the forts. On the website of UNESCO, plans are stated to create three visitor centers from the Defence Line, at Fort Pampus, Fort bij Krommeniedijk and Fort Benoorden Spaarndam.38 The first two have been developed into museums where focus has been placed on
33 The different new functions of forts of the Defence Line have been described in: T. Lycklama, A.J.T Goorts, A.C. Riefel and E. van der Woude. De Stelling van Amsterdam bekent kleur. Van erfgoedlocatie naar toeristische trekpleister van wereldformaat, Bureau voor Ruimte & Vrije Tijd, 2016.
34 Fort bij Krommeniedijk, Stelling van Amsterdam, accessed 21-08-2020, https://www.stellingvanamsterdam.nl/nl/forten/de-stelling-op-de-kaart/detailpagina- fort/q/id/144/title/fort-k-ijk-fort-bij-krommeniedijk.
Forteiland Pampus, Stelling van Amsterdam, accessed 21-08- 2020.https://www.stellingvanamsterdam.nl/nl/forteiland-pampus.
35 Website of Fort bij Edam, accessed 21-08-2020. https://www.fortbijedam.nl 36 Fort aan den Nekkerweg, Stelling van Amsterdam, accessed 21-08-2020. https://www.stellingvanamsterdam.nl/nl/fort-resort-beemster-fort-aan-de-nekkerweg
Fort Resort Beemster, accessed 21-08-2020. https://www.fortresortbeemster.nl/ 37 More than 125 elements of the Defence Line are provincial heritage monuments and around 25 are state monuments. Website of Unesco World Heritage, accessed 21-08-2020. https://whc.unesco.org/en/list/759/ 38 Website of Unesco World Heritage, accessed 21-08-2020. https://whc.unesco.org/en/list/759/ 23 experience and education, linking the forts to the history of the Defence Line.39 However, this has not been the case for Fort benoorden Spaarndam, for unknown reasons. After having been neglected for over thirty years since the 1970s, the buildings and the area surrounding Fort benoorden Spaarndam attracted the interest of different parties at the beginning of the twenty-first century. These parties are concerned about the future use of the fort and the surrounding area and about the preservation of its history and paintings. Officially, Fort benoorden Spaarndam is still owned by the Ministry of Defense, but Recreatieschap Spaarnwoude is the functioning owner, meaning that they make decisions regarding the use of the fort. The Recreatieschap is a group managing the use and development of the general area of Spaarnwoude, such as the nature and recreation options.40 They are also managing the developing plans for the future of the fort and initiated research into its history and conservation needs. One of the big parties working together with the Recreatieschap is Stichting Krayenhoff, a foundation which was established in the 1990s to open the other fort in Spaarndam, Fort bezuiden Spaarndam, for a bigger public. After this project was finished, they shifted their attention to Fort benoorden Spaarndam in 2003 and started research into the fort and the possibilities for its future. Stichting Krayenhoff and their volunteers since have been involved in the uncovering of the paintings and cleaning of the fort.41 Another party involved in the future of the fort is BOEi, a company focused on restoration and creating a new destination for monuments.42 This company is currently conducting a research into the interest and possibilities of involvement of the local communities, to create a support base for possible plans.43
2.3 Preservation of the wall paintings Due to the bad condition of the fort and the wall paintings, the future of the fort is still uncertain. The conservational issues are still being investigated at the time of writing and are being taken into account in the development of the plans for the fort. It is still unknown how and if the wall paintings will be incorporated within this new function. The large amount of paintings, combined with the historical context of the fort and the fact that this fort has been relatively unaltered since the 1950s, make it a unique and valuable example of military history, which gives an interesting look into the use of the fort in the first half of the twentieth
39 “Belevingsroutes”, Pampus, accessed 20-07-2020, https://www.pampus.nl/op- pampus/belevingsroutes/ Fort Kijk, Forten.nl, accessed 20-07-2020, https://forten.nl/forten/fort-bij-krommeniedijk-fort-kijk/ 40 “Visie”, Spaarnwoude.nl, accessed 20-08-2020, https://www.spaarnwoude.nl/visie. 41 Wijnen, Muurschilderingen en Decoraties, 15. 42 Website BOEi, accessed 19-08-2020. https://www.boei.nl/. 43 Participation project ‘Het Benoorden’, accessed 19-08-2020, https://www.hetbenoorden.nl/.
24 century. This makes it desirable to save the paintings in situ,keeping the connection to their historical context. However, the conservation of the paintings might prove to be very difficult or impossible because of the hard to control the indoor climate conditions in the fort. A stable and controllable indoor climate is needed to prevent further degradation and the paintings should be consolidated to prevent further loss. Many paintings are damaged or lost to a great extent or have not been uncovered fully. Enough budget and time are needed to treat the problems and restore the building and paintings. To be able to preserve the paintings, enough interest and financial options are needed. It is not likely that the wall paintings can be removed in a strappo method, which has been used on fresco paintings in the past, because of the absence of a thick stucco layer. In general it is clear that if an interested support base for the fort is not found and preventive measurements are not taken, the fort and the wall paintings will degrade further, resulting in the loss of important cultural heritage. A new function for the fort can, on the one hand, be seen as a possible endangering factor for the preservation of the fort and wall paintings, because of changes, but on the other hand it can create a renewed interest in the fort as a whole, resulting in possibly more interest in the paintings and the generation of an income to create a sustainable future for the fort.
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Chapter 3: Architectural paint research in room 23
3.1 Introduction room 23 In order to test the use of Blender for Fort benoorden Spaarndam, architectural paint research has been carried out in room 23. Architectural paint research is the area of research in which the historical layer buildup of an object (such as an object, a room or a whole building) is studied. The aim of this research was to create an overview of the different layers present in room 23 and to connect these to the different phases of use of the fort. Because of the size of this thesis, this research has been limited to one room. In the future it might be possible to do architectural paint research within the whole fort and create a model of the complete fort. Room 23 has been selected as the pilot case study to carry out architectural paint research and for the creation of the 3D-model. This room was chosen because of its high amount of different kinds of drawings and paintings and its accessibility during the investigation. This room has the same shape as most of the rooms in the fort, and the large amount of paintings makes it representable for most of the rooms in the fort.
Figure 28 Location of room 23 in red. Source: Z. Ziegelaar
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Room 23 is located in the main building, next to the central hallway (fig. 28). Connecting room 23 and the hallway are smaller spaces, used as storage space and toilets. It is, like most of the rooms in the fort, a rectangular shape with a vaulted ceiling. This room is described on the map of the fort as the hospital room and consisted of two separate areas, the ‘Ziekenlokaal’ (23a) and the ‘Verbandplaats’ (23b) (fig. 28) As indicated on the image, two walls Figure 259 Wall near hallway in room 21. Source: author. had been used to create a division from the small hallway and within the room. These walls have been lost but are thought to be similarly to walls that are still present in room 20 and 21 (fig. 29). These rooms were meant for high ranked officials, who got more ‘luxuries’, such as more privacy and a wooden floor. Room 21 still contains this division, showing how this division might have looked for room 23. Currently, room 23 has a concrete floor, but it is possible that it had a wooden floor similar to room 20, because of the more special function of the room. The hospital room as visible in Fort aan den Ham contains a wooden floor in part of the room (fig. 30 and 31.), so it is possible that this has also been the case in this fort.
Figure 30 Hospital room at Fort aan den Ham. Source: https://www.fortaandenham.nl/cms/fort-rondleiding/
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Figure 31 Hospital room Fort aan den Ham. Source: https://www.fortaandenham.nl/cms/fort-rondleiding/
3.2 Research techniques To get a better insight in the layer build-up of the room different research techniques have been used and the results of this research will be summarized in the following chapter. First, the room was documented by taking photographs and measurements. Already present damages were studied with a Dinolite microscope camera, to gain a better insight in the layer build-up. Next to that, stratigraphies were made by scraping layers of paint off with a scalpel, to create an overview of the present layers. However, this was very difficult because of the bad condition of the paint layers, resulting in delamination and flaking of the paint layers. Because of this, creating color-steps in which all layers were clearly visible was not possible on every wall. An overview of the stratigraphies has been included in appendix 3. To help interpret the layers found during this step, samples were taken from different locations (as indicated in appendix 4..). The aim was to study cross-sections of these samples under a microscope and possibly do SEM-EDX analysis. However, this research has been limited due to the restrictions imposed by the Covid-19 outbreak. This has resulted in that only 3 of the taken samples have been embedded and studied, with help of Luc Megens (RCE) (appendix. 5).44 Because of this small amount of samples that could be studied, the interpretation of the layer build-up is based mostly on the stratigraphies. Seeing the layer build-up under the microscope can show things that cannot be seen by the naked eye and analyzing the different pigments present can tell a lot about the paint used and helps date the
44 Due to the restrictions imposed by Covid-19, the samples taken at the fort could not be embedded and analyzed under a microscope. Luc Megens (RCE) was able to analyze 3 samples.
28 paint layer. Because of this, it could be that some layers have not been found during the creation of the color steps. However, the remaining samples might be researched in the future and the results can be adjusted accordingly.
3.3 Results of sample analysis The sample analysis carried out by Luc Megens, SEM. This research has been included in appendix 5. Sample analysis was carried out for the following samples: B1, B2 and B7. The aim was to get an overview of the layer build-up of the upper, middle and lower part of this wall.
Figure 32 Overview of sample locations Wall B (south wall). Source: Author
Sample B1 (fig.33) This sample shows at least three and possibly more white chalk-layers which are followed by a light blue chalk-layer with probably synthetic ultramarine blue pigment (layers 1-4). This is followed by again three or four white chalk-layers (layers 5-8).
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Figure 33 Sample B1
Sample B2 (fig. 34 and 35) This sample has been taken from the area where the upper part of the wall and the lower part meet, where the black and blue lines have been applied. Because of possible overlap between these paint layers, it was expected that multiple layers were visible in the sample originating from the same phase. The sample has split in two parts. Fig.42 shows the lower layers of the sample. First a white chalk layer is visible, followed by a light blue chalk-layer (similar to the blue layer 4 of sample B1). This is followed by a grey chalk-layer containing organic black pigment. The next layer is a thin dark blue chalk-layer with synthetic ultramarine pigment, with a very thin white chalk- layer on top. A grey chalk-layer is visible as the top layer in this part of the sample. Fig. 41 shows the upper part of the sample. First, a light blue chalk-layer is visible, followed by a thin black paint layer. Thirdly a white chalk-layer is visible after which two grey layers follow. It is thought that the white and light blue layers of the first part of the sample relate to the layers as found in the stratigraphies of the upper part of the wall. The following grey and blue layers could be the from the third phase (see table 1). The next grey and light-blue layers, together with the black paint layer, probably relate to the fourth phase (with the stenciled decoration, see table 1.)
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Figure 34 Cross-section of the upper part of sample B2 (was first upside down). Source: Luc Megens, RCE.
Figure 35 Cross-section of the bottom part of sample B2 (was first upside down). Source: Luc Megens, RCE.
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Sample B7 (fig. 36 and 37)
Figure 36 Sample B7, upper part. Source: Luc Megens, RCE.
Figure 7 Sample B7, lower part. Source: Luc Megens, RCE.
On a white chalk-layer follow two grey layers containing organic black pigment (layers 1-3). This is followed by blue layer (layer 4), made up of chalk and synthetic ultramarine (similar to layer 4 in sample B2.). After this comes a grey layer (no. 5) and a thin white chalk-layer (no. 6), followed by two grey layers (no. 7 and 8). This analysis has shown that the build-up of the upper part of the wall is relatively simple, only containing white layers and one light blue layer. The lower part of the wall contains a white layer that was probably a preparatory layer. The second layer, a grey, can be regarded as the first finishing layer.
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3.4 Results of stratigraphies The stratigraphies have been created on different walls and in different areas of the wall, to find out if there are differences in paint layers between the layers and within the walls. The decorative schemes seem to have been limited to 23b. 23a has been kept more sober and is similar in layer buildup to the hallway, as visible in a stratigraphy made in the hallway (fig. 38). The upper half of the wall only contained white paint layers, while the bottom half of the wall contains white and grey paint layers. The first layer found is white, which might have been a preparatory layer but could have been used as the first phase. This is followed by a dark grey layer, possibly to give the impression of a wainscoting. Then follows another white (possibly a preparatory) layer, followed by two grey layers. This area probably has not been altered a lot over time and does not seem to contain decorations.
Figure 38. stratigraphy in hallway, photo: author
Room 23b contains more paint layers than 23a, so it is not completely clear how these phases relate to the ones found in 23b. It was found that the layer build-up of the three walls in 23b was very similar, with the exception of the north-eastern wall (wall D), which contains less layers. These layers have probably been lost due to water damage. A small area on this wall still contains the blue used in the decorative stenciling, indicating that this wall has also contained the same paint layers as the other walls. Because of this, this wall will be regarded in the same way as the other walls. The wooden wall dividing 23a and 23b has been lost, so it is unclear if the paint layers found on the concrete walls have been used here as well. A difference in paint layers between the upper part of the wall and the lower part has been found for most of the phases in room 23b, creating a division of the wall or the indication of a wainscoting. This makes relating the paint layers found on the upper and lower parts of the wall more difficult, because certain areas could have been overpainted more often. The
33 upper part of the wall is relatively simple. The cross-sections of the samples and the stratigraphies indicate that five different decorative phases have been present. A preparatory chalk-white layer has been applied on top of the grainy concrete wall. This could have been one thick layer or multiple thinner ones that are hard to distinguish. One white layer has been part of a decorative phase, because the wall paintings have been applied on this layer. This white layer is followed by a light blue layer, which has been the second paint scheme. This blue layer has not been found everywhere, it has not been applied in the door-niche (fig. 40). In Strat. A-2 it has also not been found, even though it is clearly visible in the lacunae further to the left. This layer seems to have been painted around the wall paintings, allowing them to stay visible. It could be possible that the blue has not been applied to the edges of the wall, resulting in it not being visible in strat. A-2. On top of this blue layer follow at least three or more white layers (fig.41)
The height of the lower half of the wall has changed Figure 39 Stratigraphy A-1. East wall. Source: author. over time. In the most recent phase, the white upper half of the wall is connected to a grey wainscoting, which is around 110 centimeters high. Stratigraphies indicate that multiple white preparatory layers have been applied here as well, one also possible could have been part of a paint scheme (fig. 40). This is followed by a light grey layer. Following this grey layer follows an indigo blue field. At the top of this, a grey border is found, which is placed within two dark ultramarine lines. A 15-centimeter-high border in this color has also been found located at the bottom of the wall. The third paint scheme that has been found is the stenciled decoration of a geometric flower motive in different shades of blue, placed on a grey background (fig. 42). At the height of the upper dark blue line of the previous phase, a similar black line has been painted. Phases 4 and 5 are a relatively simple dark grey wainscoting. The first of these grey layers has a more grainy texture and has less coverage than the second grey layer. The following grey layer, which is the most recent layer, has better coverage and is applied slightly higher than the previous layer. Stratigraphies on the ceiling have shown that here mostly white layers have been used. However, a light blue color similar to the one on the walls has been found here, together with a orange layer. This orange layer has only been applied locally near the slogans and is though to be part of this decoration. Due to time constraint, color research into the paint layers on the doors and windows has not been included.
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Figure 40 Stratigraphy A-5 in door-niche, East wall. Source: author. Figure 41 Stratigraphy A-4, east wall. Source: author.
Figure 43 Stratigraphy on ceiling, above wall D (north wall). Source: Author. Figure 42 Wall B, south wall. Source: Author.
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3.5 Dating of the layers
Dating the paint layers found is difficult because of the relatively young age of the building and the lack of documentation of military buildings. The dating of the decorative paint schemes is an interpretation, linked to the known phases of use of the fort. Layers could have been in use for a longer time or replaced quickly. Next to this, previous paint layers could have been removed before new ones were applied or damages were overpainted, which could also result in differences in layer build-up of the four walls. However, it is likely that changes in the paint layers relate to change in the occupation and use of the fort. This has been included in table 1. The first colored phase, which is quite sober, probably relates to the first use period of use of the fort, after the build has been completed. The wall paintings have probably been added to this when the fort became occupied during the mobilization. There are multiple indications that the wall paintings and decorations have been part of an organized decoration plan or that it at least had been approved by the officials of the fort. First, the prominent placement and size of the many paintings and drawings in the fort seems to support this idea. It is unlikely that paintings on this scale were done in a way that was not approved by the fort commanders. Next to that, the light blue paint layer (of the second phase) does not cover the paintings in room 23, indicating that they were on display during multiple phases and were thus approved and enjoyed. Thirdly, it is known that different committees were active during both World Wars that aimed at providing opportunities for development and recreation for the soldiers stationed at the forts, which could have resulted in the decoration of the fort. These committees worked in consultation with a national committee called the Centrale Commissie voor Ontwikkeling en Ontspanning der Gemobiliseerde Troepen, which ensured that the fort commanders stimulated these activities.45 These committees not only organized physical training (see fig. 44) and educational courses, but also provided material for relaxation, for example by organizing ‘ontspanningsavonden’ with board games, theater and musical performances, carried out by both professionals and recruited soldiers. Next to these activities, sources also mention that the Committee organized arts and crafts related activities (‘Huisvlijt’), which were exhibited in the Hague (fig. 45) and ordered several rooms to be decorated with furniture and ‘gezelliger aankleeding’ as well.46 This makes it possible
45 Kooiman and C.J. Snijders. De Nederlandsche strijdmacht en hare mobilisatie in het jaar 1914 (Muusses, 1924), 347. 46 Kooiman and Snijders, De Nederlansche strijdmacht, 392.
36 that decoration of Fort Benoorden with paintings was done during this time, possibly as part of organized or stimulated activities. The Commissie voor Ontwikkeling en Ontspanning was also active during World War Two, organizing similar activities.47 It is possible that one of the decorative phases following the paintings, either the phase with different shades of blue or the stencil decoration, was applied during this mobilization. Similar decorated borders have been found in Fort aan den Ham and have been present in Fort bezuiden Spaarndam as well (see chapter 1.6.) indicating that decoration of the forts was more common and makes it even more probable that this was carried out in an organized way within different forts. 48 The fort was in use by Dutch soldiers for a longer time during the First World War than during the Second, so it is likely that the blue paint scheme dates from later in the First World War or the Interbellum. During the mobilization of the Second World War, the stencilling decoration might have been applied. However, dating the stencil decorations is difficult, because the use of stenciling was popular for a long time. The slogans on the ceiling have probably been applied during one of the first phases of use as well, because they refer to the use of the fort. The two slogans in room 23 relate to its function as a hospital room. One slogan is: “Early to bed and early to rise keeps a man healthy, wealthy and wise”, an old proverb referring to importance of rest, meant to inspire the soldiers in the hospital room. The other slogan has not been uncovered completely, but can be recognized as a version of the oath of Hippocrates, which is known in different versions and has been related to medicine.49 The version on the ceiling in room 23 is probably something like: “De geneeskunst is lang, het leven kort, de gelegenheid is vluchtig, de proefneming hachelijk en het oordeel moeilijk.”
47 “Ontwikkeling en Ontspanning tijdens de mobilisatie” , Oorlogsbronnen, accessed 20-07-2020. https://www.oorlogsbronnen.nl/nieuws/bron-uitgelicht-%E2%80%98ontwikkeling-en- ontspanning%E2%80%99-tijdens-de-mobilisatie
48 Blogpost 2 January 2013, Fort aan den Ham, accessed 21-08-2020, https://www.fortaandenham.nl/cms/blog/page/6/. 49 Oath of Hippocrates, Historiek.net, accessed 01-08-2020, https://historiek.net/hippocrates-ca-460- 377-v-chr/5779/. 37
Figure 44 ‘Het werk van O. en O., hoe men kruit droog moet houden’ (Bron: Beeldbank WO2, Collectie NIOD, beeldnummer 42354)
Figure 45 Huisvlijt tentoonstelling in Den Haag, 1917. Source: Nationaal Archief
Lastly, another way of dating the paint layers is by looking at the signatures that have been uncovered. Within the fort, multiple signatures were found, dating from different phases. Most of the signatures date from the 1950s, but also signatures from 1940 have been found on a door, dated 17 May 1940, indicating that a few Dutch soldiers were still stationed at the fort after the capitulation of 14 May, while waiting for further instructions.50 In room 23, multiple signatures have been found. One of the paintings has been signed G.K., while next to another painting this monogram has been written out. However, due to paint loss, this signature is hard to read (possibly G. Kottong, Kortong or Ketting. It is possible that more of the paintings in this room have been painted by G.K as well. Next to the signed paintings, three individual signatures have been written on the walls, visible on the current paint layer. Two signatures are by W. Roelands and one is by G. Tomhout/Tamhout, stating their ranks in the navy. Roelands signature is dated 18 December 1956, which falls within the period that the fort was in use by the navy as a storage space, so it makes the most sense that both
50 Wijnen, Muurschilderingen en Decoraties, 36. Zie afbeeldingen p103 van bijlage met overzicht van afbeeldingen 38
Roelands’ and Tomhout’s signatures were placed around this time. The ‘vloerbelasting’ signs that are still visible can also be linked to the use by the navy. This indicates that the walls have not been overpainted since the fort has been used by the navy, between 1948 and 1970.
Table 1. Overview of decorative phases and phases of use.
Phase Area Colors Period of use Date Phase 1 Upper half White (+ First phase of 1901-1913 paintings) use Paintings 1913-1922 possibly from during mobilization for WW1. Lower half Grey Phase 2 Upper half Light blue applied Probably 1913-1922 around the mobilization paintings WW1 Lower half Dark blue with grey part in between ultramarine lines Phase 3 Upper half Possibly still blue Mobilization 1922-1940 or white /WW2 1940-1945 Lower half Stenciled decorations on grey background. Black line in between upper and lower half of the wall. Phase 4 Upper half White After WW2 1948-1970 Lower half Grey Phase 5 Upper half White After WW2 Lower half Grey
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Chapter 4: 3D modelling technology
3D modelling has been in development since the 1970s but gained popularity since the 1990s, within different fields such as engineering, architecture and animation for movie and games. These different fields make use of 3D technology in different ways, and thus have different requirements for their models. The development of 3D technology in these fields has resulted in a wide variety of possibilities created by 3D technology, with different characteristics, equipment, price ranges and uses. All 3D models are based on data, which can either be acquired in a reality based way or through ‘nonreal’ approaches. Reality-based techniques make use of hardware and software to record reality and create a 3D model from real measurements, such as laser-scanners and structured light scanners. Nonreal approaches are based on computer graphic software or procedural modelling, where the 3D model that is being created is not based on metric results.51 The use of photogrammetry or modelling programs such as Blender fall into this category. The different data-acquisition techniques are discussed below.
4.1 Laser-scanning One of the most common ways of actively collecting data for a 3D-model is by scanning an object with lasers. The scanner emits a laser point and then records the returning laser with a sensor. The distance to object is either measured through a ‘time-of-flight’ technique which calculates the distance based on the time it takes for the laser to return (fig. 47), or through trigonometric triangulation, in which the reflection angle or intensity of the returning laser indicates the distance to the object (fig.46).52 The final product consists of "a cloud” of measurement points. These point clouds can be translated into a measurable 3D depiction of the scanned object, through computer software.53 These scanners can acquire reliable data from a range of a few centimeters up to a few kilometers, depending on the environmental characteristics and the properties of the surface and can be used on different types of equipment, such as tripods, but also moving cars, drones and airplanes. The scanner needs to record the object from different angles, so either the object or the scanner should be moved to acquire reliable data. The acquired data often needs to be ‘cleaned up’ through computer software, to remove errors, noise reduction and fill data gaps.54
51 Fabio Remondino, “Advanced 3D Recording Techniques for the Digital Documentation and Conservation of Heritage Sites and Objects,” Change Over Time 1, no. 2 (2011): 201. 52 “Laser 3D scanner vs structured light 3D scanner”, 3dnatives, accessed 20-07-2020. https://www.3dnatives.com/en/laser-3d-scanner-vs-structured-light-3d-scanner-080820194/#! 53 Karen E. Hughes and Elizabeth I. Louden,‘Bridging the Gap: Using 3-D Laser Scanning in Historic Building Documentation,’ APT Bulletin 36, nr. 2–3 (2005): 37. 54 Remondino, “Advanced 3D Recording”, 203. 40
Figure 46 Time-of-flight laser scanner principle (Van Genechten et al., 2008)
Figure 47 https://eastcoastmetrology.com/resources/applications/the-uses-and-deployment-of-large-volume-laser- scanning/ 4.2 Structured Light Scanning
Similarly to laser scanners, Structured Light Scanning also works with triangulation calculations. This technique consists of a light pattern which is projected onto an object (fig. 48). While the object or the light source moves, the pattern is distorted according to the three-dimensionality of the object, indicating its shape. A sensor or special camera can
41 register these changes in the pattern and calculate the location of the object based on measurements of the angle and distance between the light source, sensors and the object, translating it into point data. Software is used to create a 3D model based on this data.55 Because the camera can register multiple points at the same time, it works faster than laser scanners, which often only record one laser.
Figure 48 https://matterandform.net/blog/how-do-3d-scanners-work
4.3 Photogrammetry Another popular way of creating 3D models is the use of photogrammetry. This is a technique that uses digital photographs to create a 3D model, usually based on a technique called Structure from Motion. The object is recorded by a moving sensor, often a camera, taking 2D images (fig. 49). To create a 3D-model, many images of an area or object with a high degree of overlap are needed, taken from different angles but preferably with similar lighting and settings. Computer software can identify matching features in these images and create a point cloud of x, y, and z coordinates based on triangulation to calculate the three- dimensionality of the object.56 It delivers image data that require a mathematical formulation to transform the two-dimensional image measurements into three-dimensional information.57
55 “Laser 3D scanner vs structured light 3D scanner”, 3dnatives, accessed 20-07-2020. https://www.3dnatives.com/en/laser-3d-scanner-vs-structured-light-3d-scanner-080820194/#! 56 “Structure from Motion”, Humboldt State University, http://gsp.humboldt.edu/OLM/Courses/GSP_216_Online/lesson8-2/SfM.html 57 Remondino, “Advanced 3D Recording techniques”, 203. 42
Figure 49 Conceptual visualization of SfM (from Thormählen et al. 2010).
4.4 3D modelling programs Lastly, it is also possible to create a 3D-model without the presence of an object. To do this, an object is modelled by hand in a modelling program. In this case, not the object itself is a source for the collected data, but secondary sources such as images, drawings, descriptions and similar objects are interpreted and used to construct a model in a modeling program. This way, the 3D model is not based on realistic recording and metric results but is created by hand. Different computer graphics software is available for this, such as 3Ds Max, Maya, SketchUp and Blender (fig.50)58 These programs work in similar ways, but each have their own specialties, interfaces and price ranges. 3Ds Max and Maya have been developed by Autodesk and are available for around 2200 euros a year.59 SketchUp is mostly used for digital drawing, focused on architecture and is available in different forms, ranging from around 270 to 1100 euros a year.60 Blender is based on open source development and is available for download for free, making it a more accessible option compared to the other modelling programs.61
Figure 50 https://www.3dnatives.com/en/blender-3d- printing-020320204/
58 Remondino, “Advanced 3D Recording techniques”, 201. 59 Maya, Autodesk, accessed 20-07-2020. https://www.autodesk.nl/products/maya/overview?support=ADVANCED&plc=MAYA&term=1- YEAR&quantity=1#internal-link-buy 60 Overview prices, SketchUp, accessed 20-07-2020,https://www.sketchup.nl/kopen/commerciele- prijzen#overzicht 61 Blender.org, accessed 20-07-2020. https://www.blender.org/ 43
Chapter 5: Modelling process in Blender
A 3D model has been created in Blender 2.8 to test the use of the modelling program for the case of Fort benoorden Spaarndam and to compare it to other modelling techniques, as will be discussed in chapter 6. Blender is a modelling program that is available on the internet for free. It is an open source developed program, which means it is constantly being developed and improved. Some instruction and practice is needed to understand the program and the different tools, however it is a program that is generally easy to use, making it a very useful tool for cultural heritage professionals without a background in 3D technology. Tutorials or informational websites for additional explanations for Blender are widely available online as well. The 3D model created is a reconstruction of room 23 (as discussed in chapter 3) in which architectural paint research has been carried out. The aim of this model was to document the current state of the room and to visualize the different decorative paint schemes as found during the architectural paint research. First, the room has been modeled based upon the measurements taken in situ, resulting in a polygon mesh of a rectangular room. The basic shape of the room has been copied to create multiple objects in which the decorative paint schemes (and variations on the possibilities) have been visualized. The roof, doors and windows have been created as separate objects to make the modelling process easier. The first model shows the room in its current state, based on photographs taken in situ. These photographs have been incorporated in the model by adding them as ‘material’ to the faces of the mesh and unwrapping them on the model. For this step it is important to make sure the different vertices align with certain locations on the images, to make the image fit to the model exactly. If this is done incorrectly it could cause distortions in the image. The decorative paint phases have been reconstructed in the models by adding colors as ‘material’ as well (see fig. 53-56). The colors in the room have been compared to NCS color fans during architectural paint research, resulting in a color code. This has later been translated into HEX color codes, because it could be used more easily in Blender. In this way, the color is being displayed in the model in a relatively flat way, because there is no influence from texture, reflection or discolorations within the paint, making it look less realistic. This could be improved by adding a simple concrete texture on the mesh, adding characteristics to the material such as reflection or by using different light sources in the final rendering of the model. To show how digitally restored images could be used in the model, photographs of the wall paintings in room 23 have been digitally retouched and enhanced in Gimp, a free
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image manipulation program similar to Photoshop, and applied over the colored walls (fig. 51 and 52). In future projects the paintings might be restored on a more professional level, but for the scope of this thesis it was considered sufficient to show the possibilities and give an indication of the paintings. Many of the paintings have also been lost to a great extend or not been uncovered yet, making it difficult to recreate their original appearance.
Figure 52 Painting Wall B (south Wall) after digital retouching. Source: Author. Figure 51 Painting on Wall B (south wall) before digital retouching. Source: Author
Similarly, for the aim of this thesis it was not considered essential to recreate furniture that might have been present in the room, but this could be added in the future. However, it was decided to recreate the walls that are thought to have been present in the room. These have been lost but are considered important for the experience of the room and the wall paintings. Because little information is known about the colors on these walls, they have been carried out in white, to show the uncertainty of these objects in relation to the rest of the model. The same has been done for the floor, of which it is not certain that it has been present in the room originally.
Different ways of exporting the model from Blender are available, using different extensions such as FBX and glTF, which can be read by most computers in an 3D-viewer or shown in an online 3D-viewer. In this way, the model can be used within multiple other programs and formats. The model can also be published on Sketchfab, an online platform for sharing 3D
45 models. On this website, models created can be viewed or downloaded (some for free, some for a small fee) and incorporated in your own model in Blender. On Sketchfab, models can also easily be shared, creating a viewable 3D model, in which references and notes can be added.62
Figure 53 Current state visualized in 3D model in Blender. Source: author.
Figure 54 First decorative phase with wall paintings, visualized in 3D model in Blender. Source: Author.
62 Sketchfab.com, accessed 20-07-2020, https://sketchfab.com/feed. 46
Figure 55 Second decorative phase, visualized in 3D model in Blender. Source: Author.
Figure 56 Third decorative phase, visualized in 3D model in Blender. Source: Author.
Chapter 6: Possibilities 3D models
To test the applicability and possibilities of the 3D models created in Blender for Fort Benoorden, it is important to compare it to the other 3D technologies available, as discussed in chapter 4. This will be done for three categories: documentation, visualization and dissemination. The aim of this is to create an insight into which modelling technology fits best to the different needs and aims of these areas. Additionally, examples of the use of these technologies for historic interior related projects are included to see practical possibilities.
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6.1 Documentation
Documentation is an important part of dealing with historic interiors, to safeguard information and to record a state before restoration or to carry out damage mapping. For Fort Benoorden it is important to document and record the current state of both the structure of the fort and the interior decorations. In the current state, a lot of information is visible about the use of the fort before it has been altered (except for scraping). It is important to document the damages and the state of the wall paintings, so it can be compared to later changes. The experience of how a specific object relates to the interior or how different elements of the interior relate to each other is an important area of focus. For example, a wall painting is created as part of a room, so the room or building it has been created in is an important part of its meaning and value. When this context is missing, an important part of the object is lost. Seeing and experiencing an object within its context in a three-dimensional way can give more information about the relationship between the different elements in an interior, incorporating information that could not be visualized to this extend in two-dimensional images. Next to this, complex shapes or decorations within an interior can be studied easier in 3D images than photographs. Currently, within historic interior projects, buildings are recorded by taking photographs and describing parts of the room in a document. There is no standard way of damage mapping or making condition reports. Often this is still done in a two-dimensional way, with photographs, drawings and written texts. These two-dimensional documentation techniques can be sufficiently useful in situ and for small-scale projects, but are not always as useful in the case of complex projects such as big buildings, ensembles or richly ornamented interiors. Documenting in a digital and three-dimensional way makes the damage mapping and documentation more accessible for further research, easier to save all information in the same place and easier to adjust and use. It also improves the understanding of the relationship of different elements, by visualizing the three- dimensionality of an interior.63 The three-dimensionality can help map damages in a way that
63 According to information scientist Colin Ware, a visualization can promote understanding in five ways: 1. Facilitate the cognition of large amounts of data 2. Promote the perception of unanticipated emergent properties 3. Highlights problems in data quality 4. Makes clear the relationship of large- and small-scale features 5. Helps to formulate hypotheses
48 is easier to visualize in one damage mapping, instead of having to create multiple mappings. In this way, the interior can also be experienced as an interior instead of as ‘flat’ images, making it easier to compare documented damages to each other and to the real object, for example when surveying changes to the condition.
Another relatively cheap and accessible way of documenting the fort could be the use of photogrammetry. Through photogrammetry, the fort can be documented with consumer grade cameras or even smartphones to create relatively realistic 3D models, which could be enough for documentational purposes. This is for example being used to document buildings that are at risk of being damaged or destroyed, such as buildings in conflict areas or warzones. Projects aimed at documenting cultural heritage in Syria and Iraq make use of a combination of professional photogrammetric imagery, images taken by locals and images that are available on the internet.64 The use of photogrammetry for documenting these buildings is a useful way of ‘saving’ these buildings from a distance and recording them for future studies, with little resources and in a more extensive way than normal photographs can do. However, photogrammetry has some disadvantages. It requires the use of software (and possible an experienced person) to filter out noise in the recording. Next to that, to obtain a good quality model, it is best to have many images with controlled lighting conditions, which might not be possible for every project. In the fort the lighting can be controlled to a great extend so photogrammetry could be a possibility. Next to that, for conservation and restoration purposes it might be necessary to obtain more information about the exact measurements and a realistic surface texture, which is not included in photogrammetry, but can be acquired through laser scanning techniques. Laser scanning technology is currently the most used way for documenting buildings, because of the possibility of recording shapes and surface textures accurately, which can then be studied in high detail and from all sides on a computer. Long range laser scanning can be used to document large areas, for example documenting the structure of a building. Short range scanners and structured light work best on smaller objects and can give a more detailed recording of surface texture. This can be very useful for documentation in general but could also be used to survey the condition of a room or object and document damages.
Frischer, Bernard, and Anastasia Dakouri-Hild. Beyond Illustration: 2D and 3D Technologies as Tools for Discovery in Archaeology, (BAR International Series 1805. Oxford: Archaeopress, 2008), V.
64 W. Wahbeh, and S. Nebiker. ‘Three Dimensional Reconstruction Workflows for Lost Cultural Heritage Monuments Exploiting Public Domain and Professional Photogrammetric Imagery.’ ISPRS Annals of Photogrammetry, Remote Sensing and Spatial Information Sciences IV-2/W2 (17 augustus 2017): 319–25. 49
Next to this, accurately recording the surface with laser-scanners can create insight into degradation of an object, for example when cracks in a wall start to become bigger. Research done in the St. Anne’s Church in Warsaw shows how using laser scanning and photogrammetry can help in the documentation and conservation of the building, both the structural elements as the painted mural on the chapel dome.65 The church has been modelled using both photogrammetry and laser-scanning, to compare the quality of the recording and to get the advantages of implementing the color texture from photogrammetry. By scanning the chapel dome with laser-scanning from a scaffolding, measurements could be taken to calculate for structural treatment for the building. From the photogrammetric model, a panoramic unwrapping of the mural painting was made (fig.57), making it easier to study the composition of the painting in a high-resolution image. Mapping of the condition was also done on this image (fig. 58), but the authors state that this might be done directly in the model in the future. The model, made by laser-scanning, was used to analyze the current state of the mural paintings, for example to calculate the depth of cracks and thicknesses of layers, because of the high accuracy of the model. Scanning the building again in the future could be used to monitor the condition of the building, indicating new damages, causes of damage and track the rate of deterioration.
Figure 57 Point cloud 3D model of the dome of the chapel obtained by photogrammetric measurements before the conservation works. Source: Contribution of e-Documentation to Technical Rescue Works and Conservation of the Mural Painting of the Dome of Blessed Ladislaus’ Chapel in St. Anne’s Church in Warsaw”,
65 Katarzyna Górecka, Ryszard Malarski, Piotr Pawlowski, Marek Sklodowski, “Contribution of e- Documentation to Technical Rescue Works and Conservation of the Mural Painting of the Dome of Blessed Ladislaus’ Chapel in St. Anne’s Church in Warsaw”, in: Digital Heritage. Progress in Cultural Heritage, ed. By M. Ioannides et al., (Nicosia, Cyprus: 7th International Conference, EuroMed 2018): 667-676. 50
Figure 58 A Mapping of the destruction of the painting layers. Source: Contribution of e-Documentation to Technical Rescue Works and Conservation of the Mural Painting of the Dome of Blessed Ladislaus’ Chapel in St. Anne’s Church in Warsaw”.
Research into the use of different 3D scanning techniques for the documentation of the craquelure on Vermeer’s painting ‘Girl with a Pearl Earring’ has shown that these techniques can be used to create a high-resolution image and an objective measurement of the topography of the surface. This makes it possible to digitally study the surface up close, but also enables data comparison of craquelure patterns.66 Similarly, the use of close-range scanners can be used to study the topography of wall paintings. However, this is mostly used for smaller objects, because scanning will take a lot of time. The big amount of data will also result in big models, so creating a full interior with high resolution surfaces might be too big to render on websites anyway. For big areas or objects, it is best to use a long-range scanner, which still gives a relatively good and reality-based scanning of the surface, which might be sufficient for many projects. Additionally, laser scanners can be combined with other imaging tools, such as infrared cameras, to improve computer-aided conservation and restoration practices. However, laser scanners are developing quickly and scanners that can record colors are becoming more and more available as well. Differently to standard laser scanners, these scanners contain different laser sources to simultaneously record distance and colors.67 The
66 Willemijn S. Elkhuizen, Tom W. J. Callewaert, Emilien Leonhardt, Abbie Vandivere, Yu Song, Sylvia C. Pont, Jo M. P. Geraedts, and Joris Dik. ‘Comparison of Three 3D Scanning Techniques for Paintings, as Applied to Vermeer’s “Girl with a Pearl Earring”’. Heritage Science 7, nr. 1 (december 2019): 2-22. 67 Massimiliano Guarneri, Alessandro Danielis, Massimo Francucci, Mario Ferri De Collibus, Giorgio Fornetti, en Arianna Mencattini. ‘3D Remote Colorimetry and Watershed Segmentation Techniques for Fresco and Artwork Decay Monitoring and Preservation,’. Journal of Archaeological Science 46 (juni 2014): 182–190. 51 laser scanner called the RGB-ITR (Red, Green and Blue Imaging Topological Radar), developed at the ENEA UTAPRAD-DIM laboratory in Rome, has been tested for the recording of a frescoed ceiling in the Palazzo Barberini in Rome.68 This project has shown that laser-scanning techniques can also be used to create a digital replica of large painted surfaces, including the possibility of accurately documenting colors independently from environmental effects such as lighting, which could be very useful for research (fig. 59).69 Another project used this laser scanner as a method to localize surface deterioration from physical or chemical agents on hard to reach and large surfaces, such as ceiling paintings and frescoes.70
Figure 59 (a) A photo acquired by digital camera, showing the light coming inside from the windows; (b) part of the 3D model digitalized by the lasers of the RGB-ITR scanner. Source: M. Guarneri
Similarly to laser scanners, structured light scanning can be used to document the surface of an object with a high level of detail. However, the disadvantages of this technique for historic interior related projects are the fact that it needs a controlled lighting environment, because of the use of a projected light. This can be something that is hard to control, at least for the outside of a building. Next to that, because of this light source, it is hard to document big surfaces, making this technique less useful for interiors.
68 M. Guarneri, M., S. Ceccarelli, M. Ferri De Collibus, M. Francucci, and M. Ciaffi. ‘Multi- wavelengths 3D Laser Scanning for Pigment and Structural Studies on the Frescoed Ceiling ‘The Triumph of Divine Providence’’. ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLII-2/W15 (22 augustus 2019): 549–54 69 Guarneri, “Multi-wavelenghts 3D Laser Scanning”, 551. 70 Guarneri, “3D Remote Colorimetry”, 182-190. 52
Compared to photogrammetry and laser scanning techniques, which are very useful techniques to record an interior, the use of modelling programs, such as Blender, have some advantages and disadvantages. The drawback of modeling programs is the fact that the model has to be created by hand based on sources and is not an accurate recording of reality. This makes these models less useful for studying surfaces and textures in high detail or to survey the condition of damages to an object or building. Damage mapping can be carried out on another image that can then be incorporated in the model. It is not a way of recording the actual building or object, so images and textures have to be added by hand, but this does give the modeler a lot of control and freedom in creating the model. However, creating a 3D model in Blender is still a useful addition to the standard damage mapping and documentation currently being done by conservators and restorers. The program is available for free online, making it a cheap option for students or independent restorers and conservators. The basic use of Blender does not require high skilled professionals but can be learned during a workshop of a few days or through online tutorials. Images and other documentation can be easily incorporated in a model. This makes it a cheap and accessible way of bringing documentation to the next level, by approaching the documentation of a three-dimensional building in an actual three-dimensional way. A great advantage of this is also the possibility to create a digital space for combining research, as the research project Virtual Reconstructions in Transnational Research Environments – the web portal “Palaces and Parks in former East Prussia shows.71 In this project, a Virtual Museum is created for the research into cultural heritage in former East- Prussia, by using virtual reconstructions of historic houses such as the baroque palaces Schlodien and Friedrichstein, based on laser scanning of the ruins of the buildings combined with additional modelling in a modelling program to reconstruct the historic buildings based on different sources. 72 These 3D models can be used to create something called a ‘Virtual Research Environment’ or ‘Virtual Museum’. Different terms are being used, but the aims are often similar: to create a digitally accessible environment in which interdisciplinary research can be documented, connected, shown and accessed for research purposes. In this case, the 3D model serves as a ‘virtual database’, a place where the different research areas are
71Virtual Research Environments, Herder Institut, accessed 20-07-2020. https://www.herder- institut.de/en/research-projects/completed-projects/digital-3d-reconstructions-in-virtual-research- environments.html
72 Daniel Dworak and Piotr Kuroczyński. ‘Virtual Reconstruction 3.0: New Approach of Web- based Visualisation and Documentation of Lost Cultural Heritage’. In Digital Heritage. Progress in Cultural Heritage: Documentation, Preservation, and Protection, onder redactie van Marinos Ioannides, Eleanor Fink, Antonia Moropoulou, Monika Hagedorn-Saupe, Antonella Fresa, Gunnar Liestøl, Vlatka Rajcic, en Pierre Grussenmeyer, 10058:292–306. Lecture Notes in Computer Science. Cham: Springer International Publishing, 2016. 53 combined and where the research stays available, accessible and where new insights can be added. The project creates the possibility of cross-referencing different research-areas, such as architecture, art history, history and information technology, as a scholarly and didactic tool.73 The Virtual Museum that is created around the case study of manor house Schlodien is an online accessible map, in which the visitor can walk around and visit a reconstructed version of a building that is currently a ruin (fig. 60). The content in the map, for example a building, is enriched with extra visual information, paradata describing the modelling process and interpretation, metadata, context, links to websites and sources. Next to that, the viewer has the possibility to save views and share information.74 In this way, all the information is connected, accessible and stored for the future, while at the same time showing the sources used for the reconstruction of the building. A similar project could be a very interesting addition to Fort benoorden Spaarndam and the Defence Line of Amsterdam in general, to combine knowledge and research into the forts and the Defence Line in a digitally accessible database. This helps safe documentation and research for the future and creates a clear location where all research can be combined and used in an interdisciplinary way, possibly resulting in new insights.
Figure 60 Virtual Museum of Schloss Schlodien. Source: Patrimonium.net
73 Virtual Research Environments, Herder Institut, accessed 20-07-2020. https://www.herder- institut.de/en/research-projects/completed-projects/digital-3d-reconstructions-in-virtual-research- environments.html 74 Dworak, “Virtual Reconstruction 3.0”, 302-303. 54
Visualization
Creating 3D models in a modeling program also means that it can be used to visualize what is not present, which creates a lot of useful possibilities for conservation and restoration related projects. Often when dealing with historic objects or buildings, parts have been lost or altered at some stage. Digital techniques create the possibility to adjust or add information that is not based on the real object. For historic interior projects, this creates the possibilities of visualizing changes over time or reconstructing for example a decorative paint scheme based on architectural paint research. This is also the case for Fort benoorden Spaarndam. The different decorative paint schemes found during architectural paint research can be visualized in the model to give a better insight into how it was experienced in the fort. This technique is not only useful for visualizing the results of architectural paint research, but also for showing what a room has looked like in different phases of its history or what it could look like if it is restored in a certain way.
The case study of Heeswijk Castle shows the use of 3d models for virtual restoration of historic interiors. A 3D reconstruction was made of an Asian inspired cabinet dating from the 1870s, in a tower of the almost thousand-year old Heeswijk Castle, near Den Bosch in the Netherlands.75 It had a ceiling decorated with Chinese porcelain insets, wallpaper and a chinese-style pagoda balcony. Only parts of this interior were kept over time and the shape of the room had been changed. The original parts of the room that were still present, are currently being presented in the room. The rest of the room has been altered, amongst other things by adding wallpaper that is inspired by the original but is not an exact replica. This results in a reconstruction of the room with original elements, with added interpretation and alteration, that is presented as a restoration of the original.76 Because of the alterations to the room and the loss of the original objects, it would be very difficult and expensive to recreate the original style of the room in situ. In this case, the use of 3d modelling created the possibility to show what the room had looked like in the 1870s (see fig.61).
75 Jonathan Gration, “Digital Anastylosis: Developing a Virtual Conservation Methodology for Historic Houses and Interiors.” In Authenticity in the Conservation of Historic Houses and Palace-Museums. Proceedings of the International Conference, 107-113. (Palais de Compiègne, 7-11 octobre 2014.): 109.
76 Gration, “Digital Anastylosis”, 109-110 55
Figure 61 3D model showing the appearance of the room around 1878. Source: Jonathan Gration.
These reconstructions of historical phases can be taken a step further by turning it into an animated movie. One project in which animation techniques have been used is the reconstruction of the House of Caecilius Iucundus. A model has been created of this Pompeian site, which has been used for different scientific purposes (fig. 62). Next to that, a movie was created with use of the 3D model, for the exhibition Pompeji, held at the Millesgarden in Stockholm in 2015-2016 (fig. 63). In this movie, the viewer experiences a tour through the reconstructed house, with added audio that describes the function of the spaces and their decoration.77 Throughout this movie, the viewer is shown an alternation of a model based on reality, together with the reconstruction. The model is based on scientifically acquired data, but was also intended for public enjoyment.78 The existing parts of the building were recorded by laser scanning techniques and image based technology, to which color was added by using digital photographs.79 In this way, the viewer experiences the
77 Emanuel Demetrescu Daniele Ferdani, Nicolò Dell’Unto, Anne-Marie Leander Touati, en Stefan Lindgren. ‘Reconstructing the Original Splendour of the House of Caecilius Iucundus. A complete methodology for virtual archaeology aimed at digital exhibition.’ SCIRES-IT - SCIentific RESearch and Information Technology 6, nr. 1 (4 augustus 2016: 52. 78 Demetrescu, ‘Reconstructing the Original Splendour’, 51. 79 Demetrescu, ‘Reconstructing the Original Splendour’, 51. 56 reconstructed building and the original at the same time. This could be a useful tool for visualizing architectural paint research, because it could simulate changes to a room over time. Within historic buildings, it is often the different phases of use and changes over time that are interesting for researchers and for visitors. This will result in a more reliable showing of historic houses, because different interpretations and uncertainties can be incorporated, and the interior can be experienced in a less static way than through photographs. The advantage of virtual reconstruction and restorations is the possibility of showing multiple phases of a building, without the need to remove original material. In a broader sense, this means that multiple narratives, multiple ‘authenticities’, can be shown. 3D models do not intervene with original material and are flexible, so new information can be added and changes can be made, when new discoveries are done or opinions are changed, which is not necessarily the case for restoration treatments. Next to this, it is also possible to visualize in the model what is original material and what interpretations have been added.
Figure 62 Snapshot of the real-time application of the reconstruction of the House of Caecilius Iucundus. Source: Emanuel Demetrescu Daniele Ferdani, Nicolò Dell’Unto, Anne-Marie Leander Touati, en Stefan Lindgren. ‘Reconstructing the Original Splendour of the House of Caecilius Iucundus. A complete methodology for virtual archaeology aimed at digital exhibition.’ SCIRES-IT - SCIentific RESearch and Information Technology 6, nr. 1 (4 augustus 2016: 52.
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Figure 63 Showing of the 3D movie created with the 3D model.
Within the field of historic interiors, restorers are dealing broad spectrum of materials and objects that are often part of an ensemble. In a complex and big environment such as a historic interior, the effects of different choices in restoring these objects or rooms are often difficult to visualize, both for the client as for the restorer. A reconstruction can be made to visualize a possible ‘original’ appearance of a room. In the model created in Blender, photographs of the paintings have been incorporated that have been digitally restored and the stenciling has been recreated to show what these might have looked like when they were applied in the fort. The models could also show different effects of treatments, such as visualizing what certain retouches or cleaning will do to an object or how a room can be experienced when wall paintings have been restored, without having to touch the actual object. For a commissioner of a restoration project or a restorer this could be useful to show different options of treatment to help make a decision. A 3D model of Fort Benoorden can be used to show possible investors what the result of restorations can be. Digital reconstructions can also be used to visualize restoration treatment, for example to test out different options or show a client or audience what the effect of possible treatment will be.
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Dissemination
Lastly, it is important that the fort and its history can be experienced by people and the information can be conveyed to them in an understandable way. For this, 3D models create multiple useful options. Most of these options can be used in a digital way, so are not reliant on the future function of the fort. 3D models can be a very useful addition for historic interior related institutions wishing to disseminate information to a public. One of the most common ways is by using a 3D model on a website. In the quickly digitizing modern world, in which interaction with culture happens more and more online it is becoming important for museums to engage with their public through different digital channels. 3D models can be used for this, creating a way for the public to engage with cultural heritage objects in a more interactive way online, for example by being able to move them around and study all sides, or get a closer look of the object, which would not be possible in the museum. It enables interactive education and remote learning for scholarly purposes, by making cultural heritage objects accessible for people all over the world, without needing access to the museum. Making cultural heritage objects or sites accessible on the web helps create a bond between people and the object and create a link between the past and the present. Next to this, 3D models can help reach a broader audience and create awareness for lesser known or harder to reach museums and sites, because it creates accessibility to cultural heritage that otherwise would not be possible, either because of its location, but also due to conservational issues. For example, the cave paintings discovered in France, near Lascaux and Chauvet can be experienced through a 3D model online. After the cave-paintings of Lascaux were discovered in the 1940s, it quickly became a popular tourist attraction. However, the additions to make the cave accessible and the thousands of tourists that visited affected the climate in the cave, resulting in degradation of the paintings.80 To be able to preserve the wall paintings, it was decided to close the cave off for visitors and to document the cave trough the creation of a digital 3D reconstruction. 81 In this way, the public can experience the cave in a more extensive way than through photographs, while the original paintings will be preserved. Blender is a good program for this purpose, because the modeler is in control of how detailed and realistic the model becomes. A relatively simple model can already be a very useful tool on a website.
80 Robert Hewison, “What's at stake in digitising heritage sites such as the Lascaux cave?”, Apollo Magazine, 28 November 2016, accessed through: https://www.apollo-magazine.com/digitising- heritage-sites-lascaux-cave/) 81 Lascaux II and III, Archeologie.culture.fr, accessed 20-07-2020. https://archeologie.culture.fr/lascaux/en/lascaux-ii-and-iii 59
A second option for Fort Benoorden is to use the 3D model in situ, for example as a video presentation, on interactive screens or as immersive experience through Virtual or Augmented Reality. Different possibilities are available to make the public engage with the collections in a more interactive way, such as audio-tours and screens where the visitor can go to find more information about certain objects. Contemporary museumgoers have been found to seek an experience that is interactive, gives sensory and emotional stimulation and in which playful and educational elements are combined.82 A personalized, emotional and participatory experience with culture is highly valued, making the visitor a part of the story.83 3D models have the advantage of creating an even more participatory experience. Possibilities include the use of an app on a mobile device such as a smartphone or tablet that gives additional information in exhibitions, or ‘multi-touch tables’, which are tables with an incorporated screen on which people can interact with content in a collaborative way.84 This creates a space for activities related to the exhibition, for groups of school children for example, or purely for entertaining content.85 These options also create a way in which the visitor can interact with objects that are vulnerable or too precious to be handled, such as ancient manuscripts or light-sensitive objects and make the collection that is not on display more accessible to the public, for example by providing a digital representation of objects in the depot. For the dissemination of information and engaging with the public, the choice for the most suitable modelling technique depends on the aims of the model and the kind of information that the institution wants to communicate to their public. For a website a more simplified model might be better, because models with high resolution and detail can be too big to render on a website. Within exhibitions, visualizations and animations can show additional information to the object on display. A next step is to create even more immersion into a collection or interior, by using Augmented or Virtual Reality. With the use of glasses, the public can be immersed in a reconstructed building and experience cultural heritage and history, from anywhere in the world and without needing the actual object. In this way, Fort benoorden Spaarndam coud be experienced through a 3D model even if the wall paintings can not be saved or the fort can not be accessed. The project ‘Nefertari: Journey to Eternity” shows how the tomb of Nefertari
82 Pierre Balloffet, François H. Courvoisier and Joëlle Lagier. 'From Museum to Amusement Park: The Opportunities and Risks of Edutainment,' International Journal of Arts Management 16, no. 2 (Winter 2014): 5.
83 Balloffet, ‘From Museum to Amusement Park’, 9. 84 Chris Creed, Joseph Sivell, and John Sear. ‘Multi-Touch Tables for Exploring Heritage Content in Public Spaces’. In Visual Heritage in the Digital Age, (eds.) Eugene Ch’ng, Vincent Gaffney, and Henry Chapman, (Springer Series on Cultural Computing. London: Springer London, 2013): 68. 85 Creed, ‘Multi-Touch Tables’, 68. 60 in Egypt can be experienced from home. A virtual reality experience has been made available of the tomb of Nefertari, to which access has been limited due to conservation concerns (fig. 64). Developed as a collaboration between a VR developer called Experius VR and the streaming service CuriosityStream, the tomb has been made available for a large public through 3D scanning technology and photographs. The VR experience lets viewers take a virtual tour through the tomb, with interactive elements that share details of the site’s history, art and construction.86 A similar experience of the fort can be created, to experience the fort at home or showing visualizations of the different decorative phases. This could be a useful addition when the function of the fort results in limited access or the wall paintings not being visible.
Figure 64 Still from the VR experience. Source: Herodus Techne, 2018.
Finally, a 3D model of the fort can also be used for the creation of a ‘serious game’. A ‘serious game’ is an application aimed to make learning about cultural heritage more accessible to a bigger public through game technology. One example is the ‘serious game’ created for the visualization of Fort Ross (Fort Ross Virtual Warehouse) in California (fig. 65). The games generate innovative forms of situated and spatial knowledge, where the public becomes immersed in history and becomes a participant instead of only observer.87
86 VR Tour, Nefertari: journey to Eternity, Smithsonian Magazine, accessed 20-07-2020, https://www.smithsonianmag.com/smart-news/take-vr-tour-egyptian-queens-elaborate-tomb- 180969597/.
87 Nicola Lercari, Maurizio Forte, and Llonel Onsurez, ‘Multimodal reconstruction of landscape in serious games for heritage: An insight on the creation of Fort Ross Virtual Warehouse serious game’. 61
Figure 65 Still from the serious game of Fort Ross Virtual Warehouse. Source: Multimodal Reconstruction of Landscape in Serious Games for Heritage. An insight on the creation of Fort Ross Virtual Warehouse serious game Chapter 7: Limitations 7.1 Limitations of 3D models As discussed above, the development of digital techniques can create new possibilities for the field of cultural heritage, but it also contains negative sides and implications. Some thoughts on the disadvantages, limitations and negative implications of digital techniques will be discussed in this chapter. This does not mean that digital techniques should be avoided all together, but both the creators and the users of 3D models should be aware of the limitations. The (still unknown) implications of the digitalization of cultural heritage in general should also be kept in mind during conservation and restoration projects. From the early stages of its development, there was already some awareness about the negative sides of digital modelling technology, as articles from the first half of the 1990s show.88 An article in New Scientist warns for the persuasive qualities of a ‘glitzy, colourful presentation’ and the lack of quality control and academic standards for computer-based
In 2013 Digital Heritage International Congress (DigitalHeritage), 231–38. Marseille, France: IEEE, 2013. 88 P. Miller, P., Richards, J.m ‘The Good, the Bad and the Downright Misleading: archaeological adoption of computer visualization. In: Proceedings of the 22nd CAA Conference 60. (eds.) Hugget, J., Ryan, N. (Tempus Reparatum BAR International Series, Oxford), 1994. And Vincent Kiernan, "Lies, damned lies and slick graphics." NewScientist, 5 March 1994. Accessed through: https://www.newscientist.com/article/mg14119151-800-lies-damned-lies-and-slick-graphics/
62 visualizations.89 3D models and visualizations can be highly realistic, which on the one hand is a good thing, but realistic models could easily be interpreted as the truth. Compared to two-dimensional images, models carry a relatively high degree of authenticity, resulting in the past being presented as a known reality.90 With the technological developments increasing the possibilities of creating realistic and detailed models, this should be kept in mind. Next to that, the digitalization of the cultural heritage field, and the edutainment trend in general, is sometimes regarded as a negative development. Visually attractive additions and experiences in museums could become more important than the actual object and result in loss of a critical perspective. Another possible disadvantage of 3D models is the loss of materiality, traces of use and the feeling of authenticity. The surface of an object is an important carrier of information. By using close-range laser-scanning techniques, the texture of a model can be recreated very closely, but other modeling techniques often result in a less realistic texture. Some less visible information can get lost, as well as the patina and a sense of authenticity, making the object less connected to its history and be experienced in a different way. This shows that 3D models are not a perfect replacement of the real object, but mainly a useful addition.91 Next to that, the 3D model that is presented is often seen apart from the environment in which it has been developed, resulting in loss of the academic discussion, references and context connected to the model.92 This disconnection between the models and the academic research that it is based on is a phenomenon that is often discussed, but for which no clear solution has been created yet. This problem arises because of multiple reasons. Firstly, there is no clear methodology for creating 3D models for cultural heritage, because of the interdisciplinary origin and development of the technology in fields where academic values and authenticity are not the main focus. This has resulted in scattering of guidelines and principles for creating and using 3D models. It is not always clear what the aims of a 3D reconstruction are, or how it has been created. Besides internationally recognized principles for the use of computer-based visualizations, like the London Charter (discussed below), there is no clear standard about how to deal with documentation, visualization and preservation of 3D models in a scientific context.93
89 Vincent Kiernan, "Lies, damned lies and slick graphics." NewScientist, 5 March 1994. Accessed through: https://www.newscientist.com/article/mg14119151-800-lies-damned-lies-and-slick-graphics/.
90 Miller, ‘The Good, the Bad and the Downright Misleading’, 20. 91 Stiller, Juliane, and Dirk Wintergrün. ‘Digital Reconstruction in Historical Research and Its Implications for Virtual Research Environments’. In 3D Research Challenges in Cultural Heritage II, (red.) Sander Münster, Mieke Pfarr-Harfst, Piotr Kuroczyński, and Marinos Ioannides, (Cham: Springer International Publishing, 2016), 50.
92 Miller, ‘The Good, the Bad and the Downright Misleading’, 20. 93 Dworak, “Virtual Reconstruction 3.0”, 293. 63
Next to that, 3d modelling software and equipment was (and still can be) quite expensive and difficult to use, so it was often funded by large commercial organizations attracted by the media attention and public interest in archaeological projects.94 This could result in a conflict of interests and a need for spectacular visual results. Similarly, cultural heritage projects for which 3D modelling is used are often a collaboration between cultural heritage professionals and computer scientists, resulting in possible loss of control over the modelling process and creating a gap between the academic research and the model. Thirdly, it has proven difficult to incorporate or show uncertainties, interpretations, sources and multiple authenticities in the dissemination of 3D models.95 Lastly, the rapidly evolving digital technologies raise questions about the preservation of digital data. There is a need for coherence in the use and storage of cultural heritage documented in a digital way, to maintain accessibility to the information.
7.2 Principles and guidelines In response to these problems, different standards and guidelines were created, of which the London Charter is the most well-known. It was drafted in 2006 to set principles for visualization methods and their outcomes in heritage contexts, emphasizing the need for systematic documentation and evaluation of the used methods, aims of the model and the decisions made during the modelling process, to ensure intellectual integrity.96 Principle 4.4 of the Charter states: “It should be made clear to users what a computer-based visualization seeks to represent, for example the existing state, an evidence-based restoration or an hypothetical reconstruction of a cultural heritage object or site, and the extent and nature of any factual uncertainty.”97 Next to that, documentation of decisions should make clear the “relationship between research sources, implicit knowledge, explicit reasoning, and visualization-based outcomes”.98 These principles stress the importance of communicating the aim of the model and the decision-making process to the public. In 2011, the Sevilla Principles were published, which have highlighted the need for the formalization of reconstructive processes.99 These principles aim make the guidelines of the London Charter
94 “Miller, ‘The Good, the Bad and the Downright Misleading’, 20. 95 Stiller, ‘Digital Reconstruction in Historical Research’, 47 96 The London Charter, accessed through http://www.londoncharter.org/, accessed on 17-08-2020. 97 Principle 4.4 of the London Charter, accessed through http://www.londoncharter.org/, accessed on 17-08-2020. 98 Principle 4. 6 of the London Charter, accessed through http://www.londoncharter.org/, accessed on 17-08-2020. 99 Fabrizion Apollonio, ‘Classification Schemes for Visualization of Uncertainty in Digital Hypothetical Reconstruction’. In 3D Research Challenges in Cultural Heritage II, (eds) Sander Münster, Mieke Pfarr-Harfst, Piotr Kuroczyński, and Marinos Ioannides, (Cham: Springer International Publishing, 2016.), 174-175.
64 more applicable and improve its implementation for the field of archaeological heritage specifically. 100
Conclusions In this thesis, the use of 3D modelling technology for the conservation and restoration of cultural heritage has been investigated. This has been done specifically by studying the advantages and disadvantages of the use of the modelling program Blender for the case study of Fort benoorden Spaarndam. 3D modelling technology creates many useful opportunities for the field of cultural heritage, focusing on the areas of documentation, visualization and dissemination. The possibilities that Blender creates for the field of historic interiors specifically are manifold and are worth looking into by researchers, conservators and restorers and others involved in historic interior projects. The fact that Blender is available on the internet for free makes it a specifically useful for projects with limited financial options. Next to this, Blender is relatively easy to work with for people with little experience with digital modelling but can be used to create realistic 3D models. Compared to other 3D technologies such as laser-scanning, photogrammetry and structured light scanning, it is less reality-based, making it less useful for accurate documentation of surfaces and surveying the documentation of buildings over time. For research purposes, such as studying the surface of the paintings or high-detail documentation, it might be a better option to use laser scanners or structured light scanners. The advantage of digital modeling programs such as Blender is, however, the amount of control that the modeler has, which makes it possible to visualize reconstructions or make additions. Because of this, the use of Blender can be sufficient for many projects that aim to visualize an interior or virtually reconstruct a decorative phase, such as has been done for Fort benoorden Spaarndam. The model of Fort Benoorden created in Blender can be used as a space to combine and collect documentation and information from different sources, including damage mapping or as a virtual research environment. Next to this, it can be used to visualize the different decorative paint schemes present in the fort or to test out conservation and restoration treatments. Finally, it creates many possibilities to connect with an audience, through online options, but also in situ. Independent of the future of the fort, it is a way to safeguard information and to communicate this to a public, either online or in situ. On a screen or as an immersive experience. This can be done in a simplified model or through a more detailed, realistic model. The usefulness of Blender for this case study shows that this modeling program also
100 The Seville Principles, accessed through http://smartheritage.com/seville-principles/seville- principles, accessed on 20-08-2020. 65 creates possibilities for historic interior related projects in general. However, it is important to keep in mind what the aims of the project (and thus the model) are and which kind of modelling program fits these aims the best. Using multiple 3D technologies could combine the advantages of the different techniques available and help avoid specific disadvantages. Documentation about the model should be made available to ensure academic rigor. Blender is not per se the best option for every project, but it is a very accessible and sufficient option for many historic interior related projects and is a very useful addition to many projects, so should not be overlooked by conservators and restorers who think that it is too difficult or expensive.
Acknowledgements I would like to express my gratitude to Merel van Schrojenstein-Lantman for being my supervisor for this thesis and giving me useful advice and comments. Also thank you to the Conservation & Restoration instructors prof. Ella Hendriks, prof. Maarten van Bommel, prof. Rene Peschar and course coordinator dr. Maartje Stols-Witlox, for their help and support during this process.
A massive thank you to Luc Megens (Cultural Heritage Agency of the Netherlands) for helping me with the microscopy analysis of samples, especially when access to the Ateliergebouw was limited due to Covid-19 restrictions. Special gratitude is owed to Nico van der Woude (SRAL) for guiding the work in Fort benoorden Spaarndam in February and March. Special thank you to Ziegel Ziegelaar for his help and endless enthusiasm during the project and his important interest in saving the fort and the wall paintings.
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Appendix 1. Room 23
73
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Appendix 2. Overview decorations room 23
Functional paintwork The decorations that fall into this category have a function for the use of the fort, such as the room numbers and the description of the rooms on the doors. These have been added during different phases of the fort. For example, room numbers and texts have been applied multiple times on some walls (see img.). Later on, new functional paintwork has been added, when the fort was used as a place to store munition. Texts on the walls indicate the amount of weight that could be put on the floor (see img.).
Decorative The decorative paintwork is used to describe the similar paintwork that has been found in many of the rooms. This contains the grey wainscoting and the borders that have been applied with stencils. These are discussed separately from the figurative paintings, because they are not individual, artistic expressions made by hand.
Figurative paintwork The figurative paintings have been put in a different category, because of their artistic difference from the stenciling. There are different figurative paintings, painted by hand, in different rooms of the fort, in different styles. Some can be considered to be more of a drawing than a painting, some contain signatures of the artist. Different themes can be recognized. -Military themed, figures in uniforms, heraldry (of provinces and cities). -rural/farmer theme, fishers, -cartoons; suggesting humor. -women; portraits of women
slogans Slogans/sayings can be found in 3 different rooms. They have been carried out in a big size on the walls, in a colored and ornamented decorated text-box. The sayings can be interpreted as a reference to the life in the fort around the First World War, which consisted of a lot of waiting.
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German decorations In three of the rooms drawings and slogans have been found that can be linked to the German occupation of the fort. These contain SS-signs, but also drawings with German texts and signatures. Other decorations could also be from the time of the German occupation but there is too little proof to connect them to this phase for certain.
Signatures Signatures of people, probably soldiers stationed at the fort, have been found in different locations in the fort. Some of them have been dated, showing the signatures are from different phases of the use of the fort. Most of the signatures date from the 1950s, however also signatures from 1940 have been found.
Miscellaneous /modern graffiti A lot of modern graffiti and text can be found on the walls as well. These have been made with modern materials and are of low artistic and historical value, but give an insight into the loss of function of the fort and its slow decay over the last decades of the twentieth century.
Functional:
North Wall/Wall A Door to hallway
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Door to hallway West Wall/Wall C
Decorative:
All walls
77
West Wall/ Wall C
Figurative paintings
South Wall/Wall B South Wall/Wall B
78
South Wall/Wall B
East Wall/Wall A East Wall/Wall A
North Wall/Wall D North Wall/Wall D
79
North Wall/Wall D North Wall/Wall D
80
Slogans
Ceiling above North Wall/Wall D
Ceiling above South Wall/Wall B
81
Signatures
East Wall/Wall A East Wall/Wall A
East Wall/Wall A
Miscellaneous/Modern graffiti
North Wall/Wall D North Wall/Wall D
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Appendix 3. Overview stratigraphies
Stratigraphies Wall A
Strat A-1 Combination of the grey part of the wainscoting (Black) and the white area (Red)
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Black 0 Cement 1 White 2 Blue 3 White 4 White 5 Dark grey 6 Grey 7 white 8 grey
Red 0 Cement 1 White 2 Blue 3 White 4 White 5 white
Strat. A-2
0 Cement
84
1 White ground 2 Greyish white 3 White 4 Dark grey, rough 5 White/grey, 6 grey
Strat A-3
0 Concrete + white ground layer 1 Grey 2 Grey 3 Dark blue
85
4 Grey 5 White 6 Grey
Strat. A-4
0 Concrete + white ground layer 1 White ground layer 2 Grey 3 Grey-blue 4 Blue 5 Grey 6 Grey
86
Strat. A-5
A 0 Ground 1 White 2 white So at least 3 white layers, possibly more, thin. That they never changed but were just touched up? This is inside the little hallway to the door, so no blue here?? But around the corner, next to the window, there is a drawing. Is there blue there?
B 0 Cement Is 7 1 White 6 2 White 5 3 Very white 4
87
4 Grey (wainscoting) rough, 3 stripey 5 White 2 6 Grey wainscot, smooth 1
88
Wall B
Strat. B-1
Number Description 0 Concrete 1 White, thin ground layer 2 Dark grey (part of painting) 3 Light grey 4 White 5 White 6 White 7 White
Stratigraphy B-2
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0 Concrete 1 White ground layer 2 Light blue 3 White 4 White 5 White 6 White (cream)
Stratigraphy B-3
0 Concrete 1 White 2 white 3 Light blue 4 White 5 White
90
Stratigraphy B-4
0 Concrete 1 White 2 Light grey 3 Blue 4 Dark blue 5 Grey 6 Grey
91
Hallway
Strat. H-1
1 White 2 Grey 3 White 4 Grey 5 Grey
92
Ceiling
Strat. CL-1
0 Concrete 1 White 2 Grey 3 Blue 4 White 5 white
93
Strat. CL-2
1 White 2 Orange 3 White 4 Grey 5 white
94
Doors and windows
Strat. W-1
1 White 2 Blue 3 White 4 Green
95
Samples locations
96
Sample Description photo number
97
A1 Vloerbelasting-sign
A2 Light blue from stencil
98
A3 Green-blue from stencil
A4 Red from window
99
A5 Green of window
A6 Green paint of door
100
A7 (- Dark blue border on bottom of wall >B13) (This is on wall B!)
101
A8 Green above Greta
A9 Inside window-niche
102
A10 Green part above door
103
B5-A White and blue (B1)
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B5-B Blue border-line. White stayed (B2-A) behind. Upper layer is loose.
B5-b2 Test with secondelijm (B2-B)
B5-B3 -B5-B: randjes of the stencil, darkblue. (upper layer is loose). From dark blue, white stayed behind B5-B2: test with secondelijm (gel)
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B5-B3: test secondelijm + japans papier, losgesneden B5-B4: test secondelijm + japans papier facing
B5-B3 B5-B4 B5-C Black border, loose pieces
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B5-D Orange near Bliksem (B4)
107
B6-A Grey wainscot (B5)
B6-B With black (B6)
108
B6-C Dark blue background, biggest chip (B7) contains most layers
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B7 (B8) Florence, secondelijm (liquid).
110
B8 (B9) Face military man + loose piece of skin color
111
A7 Dark blue bottom border of wall (B10)
112
C1 White of wall in the hallway. Last layer of white not in sample
113
C2 Wall hallway + grey
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D1 Bloemenmeisje, grey from the hat
D2
115
D3 White near green sign
116
D4 Door near windows
P1 P1: plafond bij opengekrabt deel van oranje rood P2: wit, buiten gekleur vlak, waarschijnlijk blauw P3: in oranje veld, naast letter. Gesplitst in oranje laag, daaronder zit nog wit
P2
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P3
118
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Kleurhistorisch onderzoek naar de schilderingen in het ziekenlokaal en de verbandplaats van Fort
Benoorden Spaarndam
Onderzoeksrapport
Luc Megens
Rijkserfgoedlaboratorium
In opdracht van: UvA HB RCE Amsterdam: 2020-015 Datum: augustus 2020
Onderzoeksrapport
Kleurhistorisch onderzoek naar de schilderingen in het ziekenlokaal en de verbandplaats van Fort Benoorden Spaarndam
Datum : 21 augustus 2020 RCE Projectnummer : 2020-015 Monument nr. : NH/WN470 Auteur(s) : Luc Megens
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Toegankelijkheid van dit document
Door Rijksdienst voor het Cultureel Erfgoed (RCE) verstrekte informatie is onderhevig aan de ‘Wet openbaarheid van bestuur’ (Wob). De rapporten zijn beschikbaar via de bibliotheek van het RCE. Uitzonderingen hierop kunnen schriftelijk worden aangevraagd.
© 2020 Rijksdienst voor het Cultureel Erfgoed. Alle rechten voorbehouden. Niets uit dit rapport mag worden verveelvoudigd en/of gepubliceerd, in enige vorm of op enige wijze, zonder voorafgaande schriftelijke toestemming van de Rijksdienst voor het Cultureel Erfgoed (RCE).
Foto titelpagina: © Emma Egberts Alle andere foto’s in dit rapport tenzij anders vermeld: © Rijksdienst voor het Cultureel Erfgoed
Hoe te refereren naar dit document
Megens, L., 2020, Kleurhistorisch onderzoek naar de schilderingen in het ziekenlokaal en de verbandplaats van Fort Benoorden Spaarndam., RCE projectnummer 2020-015, Amsterdam: Rijksdienst voor het Cultureel Erfgoed, Rijkserfgoedlaboratorium.
Inhoudsopgave Samenvatting ...... 3 Objectgegevens ...... 3 1 Inleiding ...... 4 2 Resultaten en discussie ...... 5
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Samenvatting
Drie monsters zijn geanalyseerd van een wand van kamer 23, het ‘Ziekenlokaal’ (23a) en de ‘Verbandplaats’ (23b)met schilderingen uit verschillende fases. De pigmenten zijn geanalyseerd en de laagopbouw beschreven.
Objectgegevens Monument nr. : NH/WN470 Instelling : Locatie : Spaarndam Kunstenaar / Vervaardiger : Titel : Fort Benoorden Spaarndam Datering : Fort dateert eind 19e eeuw, schilderingen uit verschillende jaren
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1 Inleiding
Het fort Benoorden Spaarndam werd eind 19e eeuw gebouwd als onderdeel van de Stelling van Amsterdam en heeft gefunctioneerd tijdens WOI. Tijdens WOII is het bezet door Duitsers. Hierna is het gebruikt als munitiemagazijn. In een groot deel van de ruimtes zijn schilderingen (zowel decoratief als functioneel) teruggevonden onder de huidige witte afwerkingslaag. Deze schilderingen dateren uit verschillende fasen van het fort. Voor meer informatie raadplege men de scriptie van Emma Egberts hierover. Drie monsters zijn geanalyseerd van een wand van kamer 23, het ‘Ziekenlokaal’ (23a) en de ‘Verbandplaats’ (23b)met schilderingen uit verschillende fases.
Afbeelding 1. Overzicht van de monsterlocaties (foto Emma Egberts, UvA).
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2 Resultaten en discussie
Monsternummer FBS-B1 bovenstuk van de muur, waar nu een witte kalkverf zichtbaar is
Verfdwarsdoorsnede in opvallend gepolariseerd Backscattered Electron Image van de licht verfdwarsdoorsnede
Op drie witte kalklagen volgt een lichtblauwe (?) kalklaag met zeer weinig fijn verdeeld blauw pigment, waarschijnlijk synthetisch ultramarijnblauw. Deze laag komt overeen met de lichtblauwe laag in monster FBS-B2A. Hierop volgen nog drie of vier witte kalklagen.
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Monsternummer FBS-B2A blauwe en zwarte lijn die de bovenkant van de muurdecoratie scheiden van de 'wainscot'.
Dit monster was in tweeën gespleten. Het onderste en bovenste verflagenpakket vormen nu twee verfdwarsdoorsnedes.
Verfdwarsdoorsnede in opvallend gepolariseerd Backscattered Electron Image van de licht verfdwarsdoorsnede
Verfdwarsdoorsnede in opvallend gepolariseerd Backscattered Electron Image van de licht verfdwarsdoorsnede
Op een witte kalklaag volgt een lichtblauwe kalkverflaag, bestaande uit kalk en weinig synthetisch ultramarijnblauw (onderste foto’s). Hierop ligt een grijze kalklaag met organisch zwart pigment, gevolgd door een vrij dunne donkerblauwe kalkverflaag met synthetisch ultramarijnblauw. Deze verflaag is vergelijkbaar met de blauwe kalkverflaag in monster FBS-B7. Op de donkerblauwe laag volgt een zeer dunne witte kalklaag, met daarop een grijze kalklaag met zeer weinig bariumsulfaat. In het tweede deel van het monster (bovenste foto’s) ligt op een lichtblauwe kalklaag met zeer weinig synthetisch ultramarijnblauw een dunne zwarte verflaag met organisch zwart pigment en weinig bariumsulfaat (de witte korreltjes in het Backscattered Electron Image. Hierop volgt een witte kalklaag. Op de witte kalklaag liggen twee grijze kalklagen met grof organisch zwart pigment, welke de nu zichtbare grijze afwerking vormen.
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Monsternummer FSB-B7 Grey part of wall, dark blue background under grey
Verfdwarsdoorsnede in opvallend gepolariseerd Backscattered Electron Image van de licht verfdwarsdoorsnede
Verfdwarsdoorsnede in opvallend gepolariseerd Backscattered Electron Image van de licht verfdwarsdoorsnede
Alle verflagen zijn kalkverflagen. Op een witte kalklaag volgen twee grijze kalkverlagen met organisch zwart pigment (onderste foto’s). Er zijn geen aanwijzingen waaruit opgemaakt zou kunnen worden om hoeveel afwerkstadia het gaat. Op de bovenste grijze laag liggen wat donkere pigmentkorrels, die niet geanalyseerd konden worden, maar mogelijk synthetisch ultramarijnblauw zijn, en van de volgende laag afkomstig zijn. Hierop volgt een blauwe kalkverflaag, bestaande uit kalk en synthetisch ultramarijn blauw (bovenste foto’s). Daarop ligt een grijze kalkverflaag met grof organisch zwart pigment, gevolgd door een dunne witte kalklaag, met daarop weer twee grijze verflagen met grof organisch zwart pigment.
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Project: Fort Benoorden Spaarndam User Name: Luc Megens Company Name: RCE
Appendix 1. SEM-EDX spectra
Image Name: B1 Acc. Voltage: 20.0 kV Magnification: 150
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Image Name: B1(2) Acc. Voltage: 20.0 kV Magnification: 600
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Image Name: B1(3) Acc. Voltage: 20.0 kV Magnification: 600
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Image Name: B1(4) Acc. Voltage: 20.0 kV Magnification: 1000
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Image Name: B1(5) Acc. Voltage: 20.0 kV Magnification: 2500
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Image Name: B2A(1) Acc. Voltage: 20.0 kV Magnification: 200
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Image Name: B2A(2) Acc. Voltage: 20.0 kV Magnification: 1000
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Image Name: B2A(3) Acc. Voltage: 20.0 kV Magnification: 1000
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Image Name: B2A(4) Acc. Voltage: 20.0 kV Magnification: 200
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Image Name: B2A(5) Acc. Voltage: 20.0 kV Magnification: 750
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Image Name: B7a(1) Acc. Voltage: 20.0 kV Magnification: 200
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Image Name: B7b(1) Acc. Voltage: 20.0 kV Magnification: 200
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Project: Fort Benoorden Spaarndam User Name: Luc Megens Company Name: RCE
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