The second lecture concentrates on the collections duplicated images. By exploring the duplicates the lecture brings to the fore the slides materiality and resultant polysemy. The material disparity of the duplicated images, in terms of their framing, inversion, enlargement and magnification, are examined in the lecture. The varying material qualities cleave the same slide into two highly different images. By contrasting pairs of duplicates, the curators explore how their varying materiality offers an avenue through which the images polysemy may be unleashed. The curators question what the implications of using slides with different material properties might be when used for teaching purposes.