Many universities have declared open access policies in response to increasing interest in open access in the academic world. The next developments will be focused on open data. Huge data repositories are already used in specific fields. However, the discussion regarding open data in universities has just begun. We attempted to promote open data for digital humanities in a university library. University libraries hold rare collections, which are generally highly valued research resources. We selected a rare collection in a library, and then digitized and published it. We investigated additional data that aids a reader's understanding of the material. To promote the open data, we produced images of the resources and multiple types of interpretation texts. We displayed the digital images in an exhibition and obtained an evaluation using a survey of visitors.
