What is a DjVu file?
DjVu is a document format used for scanned books, journals, and manuals. Files commonly use the .djvu extension. A document contains page images and may also include searchable text, a table of contents, and annotations.
Page images and searchable text
Section titled “Page images and searchable text”DjVu can compress the foreground and background of a scanned page separately. Repeated shapes can share image data. This can reduce file size, but the result depends on the scan and encoding settings.
The image of a letter is not searchable text. Search and copy require a separate text layer, usually produced by optical character recognition (OCR). A document can display correctly even when that layer is absent or incomplete.
The DjVuLibre documentation describes the format and its tools.
Open a DjVu file
Section titled “Open a DjVu file”Use an app that supports DjVu. Niraqua DjVu reads files on Mac, iPhone, and iPad and can recognize text on the device.
Convert or keep the original
Section titled “Convert or keep the original”Export a PDF when the recipient or another app needs PDF. Keep the original DjVu if you want to retain the source document; conversion does not improve the original scan.
See convert DjVu to PDF and compare DjVu and PDF.