Introduction – WP 5

One of the eight work packages (WP) or key actions in the ArcLand project is Securing better exploitation of existing air-photo archives across Europe by researching, assessing and publicizing their potential for heritage interpretation and landscape conservation (WP 5). These archives are resources with great potential for cultural heritage studies.

Figure 1 A Neolithic pit-defined circle and other monuments in Kintyre, western Scotland, recorded as cropmarking on an aerial photograph taken to help map making. This is an excellent example of the serendipity effect of historic aerial photographs, where images taken for one reason, such as military intelligence or map making, have a value for other purposes – in this case for recording archaeological monuments. OS 77 081. © Crown copyright and database rights 2013 Ordnance Survey (1000020548).

The goals of WP 5 are to promote training workshops and conferences, promote the enormous potential in archives, work on guidelines and standards for aerial photo (AP) archives, address technical challenges, and encourage training in use of aerial photo archives. One of the first actions was to begin an online survey to collect basic information about existing AP archives to contribute to an overview of available material for “airborne cultural heritage studies”.

The online survey

The survey was developed with the purpose of gaining a better overview of existing archives, principally in Europe, and collecting basic information about the collections and their accessibility. Beyond collating this basic information, it is further planned to undertake the following actions:

• Develop a program to assess and document the existing resource of historical AP, including basic metadata.
• Create a digital index/portal to disseminate knowledge of collections and their content, with user guides where possible, which has a sustainable future after the ArcLand project. This would also serve to stimulate further interest and could provide a basis for a more extensive portal for AP archives.
• Attempt to identify hitherto unknown/inaccessible archives (e.g. from former USSR) and to encourage accessibility.

The survey contained a range of questions, some, like collection size, with set options, but most fields were designed for open-ended responses, such as scope, geographic area and accessibility of the collection. The open-ended responses gave valuable information, but are challenging to present in a short overview such as this. The survey was widely disseminated through ArcLand partners who were encouraged to forward it to anyone involved in aerial photography and potential holders of aerial photo archives.Here we will present an overview of some of the most basic information from the survey. From the open-ended responses we have made some generalizations. Generally, the response material contains more information about each archive than we have presented here.

Results

Table 1: Number of respondents from each country.

The responding countries listed in Table 1 shows considerable variations in the geographical range of responses, only aspects of which are related to the distribution of ArcLand partners.  Thus, while there are 57 ArcLand partners from 31 countries, Norway reported 30 archives, Finland nine, the UK eight and six from both France and Germany. The penetration of the survey is thus very patchy, but the high responses from Norway, for example, show the kind of returns that active promotion of the survey might generate in other countries in the future.

Table 2: Content types in archives

For the type of image format in responding archives Table 2 shows that photographic prints are most common. As many as 68 archives report this type of content. There are almost as many digital photo archives, 64, and 55 archives storing negatives. Only three archives report storing aerial photographs on microfiche. The total number of responses to this enquiry exceeds the 90 archives which answered the survey, as most archives store more than one content type.

Table 3: Collection size

Most of the reported archives are small (Table 3), with 36 holding a collection of less than 1.000 images. 14 archives contain up 5.000 images, 11 archives up to 10.000 images. There are 17 archives which have between 10.000 and 100.000 photographs, but only three with between 100.000 and 500.000, and one archive with between half a million and one million photographs. In addition there are actually 4 really large archives with more than 1.000.000 aerial photographs.

Table 4: Geographic areas covered by the archives

Three archives report that they cover more than one country. Archives with national cover have been reported from 16 countries. Several archives work on a national level, but with a more limited scope either geographically or thematically (e.g. railways, roads, hillforts or cultivated areas). Of the 35 regional archives, three cover federal states, the rest cover one (or more) region(s), a county or several counties or an island. Five archives cover several municipalities. The archives defined as local are those that cover a municipality, city or a smaller area. Only four of the local archives cover a very limited area, like a site or estate. As this was a field for open-ended responses, there were four replies where the geographic area could not be defined.

Table 5: Time periods covered by the archives

For 51 archives there is no indication of the time period covered. Of the other 39 archives the level of detail for periods covered differs. However, 18 archives reports holding photographs from pre-1950. Of the 21 archives which do not have photos from before World War II, eight have photos from the 1950s, while seven archives report that the origins of their collection lie within the last 20 years.

Table 6 Scope of the collection

Almost all the institutions responding to the survey are either museums or archives, and this is reflected in the scope of the collections. For 25 archives, the scope is reported to be archaeological survey, with 26 describing their scope as documenting or presenting cultural history and 13 archives reporting as both archaeological survey and cultural history. Eight archives store aerial photographs taken for mapping purposes; three archives describe the reason for photograph acquisition as military use. A few archives describe the background for their collection as either views of cities and/or landscapes or farmsteads. One collection is made for the purpose of postcard production.

Figure 2 Central Caen, Normandy, France was heavily damaged during World War II, as shown in this oblique image taken by the Royal Air Force on 2 October 1944. The reconstruction of Caen lasted until the 1960s, and little of the pre-war city remains, so photographs like this are important record of the urban fabric and the historic environment of the city. They are also powerful witnesses to historical events. NCAP_JARIC_106G_3170_0011. National Collection of Aerial Photography (aerial.rcahms.gov.uk).

Further work

This survey is an initial work and is meant to be elaborated on, as the project partners are aware that creating an overview and encouraging fuller use of aerial photo archives is a long-term task. Still, these results are a promising starting point, and there are many aspects worth further discussion.

First, the uneven geographical distribution of archives reported has been commented on above. One country, for example, reports 30 archives, while other countries reported none, even though there are members of WP 5 who work in that country. Obviously the results do not reflect the real distribution of aerial photo archives. This can have several causes. Firstly, the distribution of the survey was informal, using ArcLand partners and through a link from the ArcLand website. This makes the response rate very vulnerable to the effort of individual ArcLand partners, and the respondents’ individual interest in the ArcLand project. Varying efforts from ArcLand partners is likely to give a varying response rate. It is likely (but has not been investigated) that of several countries reporting only one archive, this is the archive of the ArcLand partners’ own institution. In Norway, where 30 archives were reported, the electronic survey was distributed to more than 700 e-mail addresses belonging to potential archive owners. It is likely that the high number of archives reported from Norway compared to the other countries is due to this wide distribution. This suggests that most European countries will have many archives that have not been reported to the ArcLand project. A key focus of taking the survey forward will be encouraging better dissemination and wider responses.

Secondly, that there are almost as many archives of digital images as of photographic prints needs discussion alongside  the few archives reporting storing negatives (though it is not specified if all are originals or copies). This may indicate that the same photos could be stored as copies in more than one archive, and also that digital archives may be copies of negatives or photographic prints, as it is known that several archives are working to digitalize their collections to make them easier to find, use and share. The same consideration should be made about collection size, as it is likely that some duplication may exist. The documentation of duplication between archives will be complex, but could help to focus effort and encourage cooperation between archives and efficiency of effort in cataloguing, digitising and storage.

Third, the geographic coverage demonstrates the large variation in archives reported. There are two international archives and 16 national, but most archives cover parts of a country, from state, region, municipality to one city or one estate. There are nine archives which report their collections to be demarcated by thematic focus, not geographic delimitations. This too, must be addressed in developing the survey, to ensure better representation.

Fourth, the reported time periods covered also show large variation, although since only 39 respondents reported dates of photography any conclusions are preliminary. Still, it would not be surprising if the other archives follow the same patterns. It is not surprising that there are few archives reporting photographs from before 1920, as flying and photography expanded enormously after World War I. Thus, there are quite a few archives with photos from the early days of systematic aerial photography, starting in the 1920s and 1930s. However, there are none? No? archives originating in the 1940s, which is a bit surprising given the emphasis on aerial photography during the Second World War – this is probably largely due to the fact that the archives did not originate until after the end of hostilities, even if the material were being collected before then. In the 1950s new collections were founded and there are also some archives which originate in the 1960s. Of the archives reporting time period, only one starts in the 1970s and one in the 1980s. However, there are more series and archives which originate in the 1990s and 2000s, probably due to the active development of commercial companies. The date ranges are probably broadly indicative, but highlight some variability in the reasons for the formation of archives that will bear further investigation and perhaps form the basis for selective targeting of the survey.

Fifth and lastly, the scope of the collections is worth comment. A large proportion of the archives (25/90) report archaeological survey as their scope, with 26 reporting cultural history, 13 both archaeological survey and cultural history and one reporting archaeological management. This means that 65 out of the 90 archives have archaeology and/or cultural history as their main focus, perhaps unsurprising given the archaeological emphasis of the ArcLand network and therefore the likely routes for dissemination of the survey. Eight archives report mapping purposes, and only three archives reported military use. This leaves 15 archives with other foci such as landscape or city views or other. There are surprisingly few archives reporting military or mapping purposes as the scope of the photo archive, compared to those reporting cultural history as their scope. Generally, there have been more resources in the military for this kind of activity, than in the cultural heritage sector. It is likely that in some cases what has been reported is the present purpose of the museum/ archive as a whole, not the scope of the aerial photo collection, which may be a small part of a much bigger archive or museum. In other cases it is likely that the photo archive is a secondary owner of the collection, and that the photographs were produced for other purposes, of which military intelligence may have been significant. Anyway, this shows that there are probably still quite a few archives out there not reported in this survey, with cultural heritage, mapping, military or other scopes, which can all be useful for cultural heritage studies.

Concluding remarks

The survey is a first step towards developing an overview of European aerial photo archives available for archaeological and cultural heritage studies. We have presented some of the results from the survey, which will hopefully inspire ArcLand participants to explore the results further. In developing the surveys further it may be useful to be more specific about the purpose and use of the survey results, to encourage further participation. We would like to emphasize the potential for further use of the information already collected, and last but not least, the existence of many archives out there, which have not been reported in this survey so far.

WP 5 of the ArcLand project is now working on an online overview and portal to the archives that are available to the public. This contact information will be made public as soon as possible, but in the meantime we encourage all who are interested to use the rich source of information for cultural heritage and landscapes studies and management that aerial photographs can provide.

Beyond publishing the survey and promoting access, further work will be advanced, perhaps by developing a systematic approach to individual countries, but also on the generic issues of generating descriptive standards for aerial photographs which is vital to indexing and efficient retrieval.