Image searching in an open photograph archive: search tactics and faced barriers in historical research

During the last decades, cultural heritage collections have been digitized, for example, for the use of academic scholars. However, earlier studies have mainly focused on the use of textual materials. Thus, little is known about how digitized photographs are used and searched in digital humanities. The aim of this paper is to investigate the applied search tactics and perceived barriers when looking for historical photographs from a digital image archive for research and writing tasks. The case archive of this study contains approximately 160,000 historical wartime photographs that are openly available. The study is based on a qualitative interview and demonstration data of 15 expert users of the image collection searching photographs for research and writing tasks. Critical incident questions yielded a total of 37 detailed real-life search examples and 158 expressed barriers to searching. Results show that expert users apply and combine different tactics (keywords, filtering and browsing) for image searching, and rarely using one tactic only is enough. During searching users face various barriers, most of them focusing on keyword searching due to the shortcomings of image metadata. Barriers were mostly in the context of the collection and tools. Although scholars have benefited from the efforts put into digitizing cultural heritage collections, providing digitized content openly online is not enough if there are no sufficient means for accessing the content. Automatic annotation methods are one option for creating metadata to improve the findability of the images. However, a better understanding of human information interaction with image data is needed to better support digitalization in the humanities in this respect.