Newspapers count among the most attractive sources for historical research. Following mass digitisation efforts over the past decades, researchers now face the problem of overabundance of materials which can no longer be managed with keyword search and basic content filtering techniques alone even though only a fraction of the overall archival record has actually been made available. This poses challenges for the contextualisation and critical assessment of these sources which can be effectively addressed using semantic enrichments based on natural language processing techniques. In this lecture Marten Düring will discuss epistemological challenges in data exploration and interface design as well as opportunities in terms of source criticism and content exploration, based on the impresso interface.