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  • Universal Viewer

    British Online Archives uses the Universal Viewer (UV) to display images and other media (PDFs, JPEGs, video, audio, etc.). The Universal Viewer is open-source software used by many renowned heritage institutions such as the British Library, the National Library of Wales, the Swedish National Archives, and the Wellcome Library.

    Note: Not every collection currently uses the UV. Some older BOA collections use a PDF viewer to display images. While not as advanced as the Universal Viewer, the PDF viewer includes a range of useful technical features such as deep zoom. We are in the process of transferring all collections onto the Universal Viewer. 

    The UV incorporates a range of unique and useful technical features, including deep zoom, OCR searching, IIIF image API, and extensible metadata fields. 

  • Viewing Documents

    You can view documents in three ways:

    • As a single page
    • As a double-page spread
    • As a gallery

  • Viewing Images

    You can navigate through images in the following ways:

    • By selecting the image thumbnails displayed on the contents bar.
    • By selecting an arrow to navigate forwards and backwards through the images.
      • Note: There are two sets of arrows displayed on the UV, both serving the same purpose.
    • By entering your desired image number directly into the box displaying your current image number.
    • If you’re using a laptop/PC, you can also use the page up/page down keys on your keyboard.


    There is also an option to view images in full-screen mode. 

    Images can be rotated through 90 degrees clockwise by selecting the rotate icon. 

  • Deep Zoom Feature

    The deep zoom feature allows you to inspect key details in a document without lowering the quality of the image. Select the plus sign (+) to zoom in and the minus sign (-) to zoom out.

    If you are using a laptop/PC you can also zoom in by scrolling up and zoom out by scrolling down. If “Mouse Click to Zoom” is toggled on in settings, you can zoom in by left-clicking and zoom out by shift + left-clicking. 

  • OCR Search

    Each image on the website has undergone Optical Character Recognition (OCR). This means that you can search for words or phrases contained within images. To search for every mention of "Royal Air Force", for instance, you should enter the phrase into the search bar. The results will be displayed on the contents bar. The relevant word or phrase will be highlighted in blue on the images. 

    Note: OCR text data is computer-generated for our documents through an automated process. While we aim for the highest quality OCR possible, due to the age and quality of the documents and the accuracy of the algorithms used, text transcriptions are not always as accurate as we would like.

  • Image Metadata

    Select Metadata to view important information about the document (Description, Contributor, Creator, Publisher, Rights, Coverage, Identifier, Licence, etc.). To minimise the tab, select Metadata.

  • Downloading Images

    To download an image, select the download button and the appropriate image size. The image will then open in a new tab. 

    If you are accessing our collections via an institutional account, there is also a function outside of the UV to download whole documents, instead of individual images.

  • Settings

    Select settings on the viewer to change things such as default language, viewing options, and zoom settings.

  • Mobile/Smaller Screens

    If you are viewing the BOA website on a mobile or a smaller screen, the UV will have slightly different features, i.e. there is no search, there is no side gallery showing image thumbnails, and metadata can be accessed by selecting the “i” button.

    More information on the UV can be found on the Universal Viewer webpage.

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