Despite the mass digitization of books, illustrations have remained more or less invisible. As an aesthetic form, illustration is conventionally positioned at the bottom of a hierarchy that places painting and sculpture at the top. The hybridity or bimediality of illustration is also problematic, the genre having fallen between the cracks of literary studies and art history. In a digital context, illustration has fared no better: new technologies can aid the editing of a literary text far more successfully that they can deal with the images that accompany it.

This paper focuses on the challenges and the implications of an AHRC-funded Big Data project that will make searchable online over a million book illustrations from the British Library's collections. The images span the late eighteenth to the early twentieth century, cover a variety of reproductive techniques (including etching, wood engraving, lithography and photography), and are taken from around 68,000 works of literature, history, geography and philosophy.

The paper identifies issues relating to the improvement of bibliographic metatdata and the analysis of the iconographic features of the images, which impact on our understanding of 'the image' in Digital Humanities and the negotiation of Big Data more generally. The work undertaken as part of the Lost Visions project allows for the further development of Illustration Studies, repositioning visual culture in the largely text-based process of digitisation and problematising modes of textual production.