# What is a DjVu file?

> Learn what a DjVu file contains, how scanned page images differ from searchable text, and how to open or convert the document.

Source: https://niraqua.com/djvu/what-is-djvu/

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

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](https://djvu.sourceforge.net/doc/) describes the format and its tools.

## Open a DjVu file

Use an app that supports DjVu. [Niraqua DjVu](https://niraqua.com/djvu/) reads files on Mac, iPhone, and iPad and can recognize text on the device.

- [Open DjVu on Mac](https://niraqua.com/djvu/open-djvu-mac/).
- [Open DjVu on iPhone or iPad](https://niraqua.com/djvu/djvu-reader-ipad/).

## 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](https://niraqua.com/djvu/djvu-to-pdf/) and [compare DjVu and PDF](https://niraqua.com/djvu/djvu-vs-pdf/).