Scholarly users of digital reproductions (so-called facsimiles) in digitized collections tend to approach the reproductions on a face value basis, but how can they be certain that what they see on the screen is "the same" as the physical source document the reproduction purports to reproduce? Digitizing institutions may provide keys for the user to unlock this kind of digital provenance, where paradata and metadata will be important, together with e.g. extant project documentation, paratextual material, and access to the uncompressed master files from which the reproduction presented on screen derives.