A DJVU file is a file which has been scanned into digital document format and provides the capability to display both images and text using advanced compression technology. DJVU stands for déjà vu, which means the file extension is frequently displayed as .DjVu. The purpose of the DJVU file format is to provide high resolution images of content, such as documents and photos, in the online environment.
DJVU files have been around since 1996 and were developed by AT&T labs in an effort to solve the problem of scanning high resolution documents into websites in order to make content such as catalogs, manuals, and newspapers readily available online. Therefore, the content contained in DJVU files includes IW44 photos in a wavelet-based compression format, bitonal JB2 images in black and white, scanned color documents, and BZZ files which are used to compress searchable text layers in documents.
DJVU files are open source, which means the file format is open standard and makes encoders for the technology readily available. The compression ratio for DJVU files can be as much as ten times better than existing formats for online documents, such as JPG, GIF, and TIFF file formats. When color files are scanned, they can be reduced to as much as 100KB (kilobits) from 30 MB (megabits). For black and white files at 300 DPI (Dots per Inch) as opposed to pixels per inch, the files can be compressed down as far as 30KB.
How to Open DJVU Files
In order to open DJVU files, you must download and install the DJVU browser plugin which is available at no cost for all of the major computing systems. The DJVU plugin is available from the Caminova website, which is the company that took over DJVU technology from AT&T labs. All you have to do is log onto Caminova.net; choose the product version that is appropriate for your operating system, the language you want to use, and then click on Download.
The DJVU plugin download is available for both 32-bit and 64-bit versions of Windows as well as Mac OS X, Linux and UNIX. Once you have downloaded the program, the installation file is very small, so the process of downloading is quite fast. You can also choose from Auto Install or Manual Install, and the option you choose will depend upon your operating system and the browser that you are using.
You can also choose to install DjVuLibre which is an enhanced version of the plugin code and provides you with a standalone viewer. This option is typically used with browsers that are designed for UNIX such as Netscape, Galeon, and Konqueror, to name a few. DJVU files can also be converted using a conversion service such as Any2DjVu.
