Djvu or pdf? What is better?

Most companies will sooner or later faces the need to introduce electronic document. Thus one of the most important issues is to choose the format in which documents will be created, stored and transmitted to other companies or remote offices. Today we compare the two formats: PDF and DjVu.

A few words about DjVu

History DjVu began in 1996. It was then a business of AT & T started work on a new format. The main task, which was given to the developers - to create technology for the storage and transmission of scanned documents, that is, in fact, documents in electronic form. But while few could have predicted that in future the company will be exchanged through a global network of treaties and acts. Therefore, under the documents were understood scanned magazines, newspapers, books, technical documentation. In 1998 appeared the first plug-ins for viewing DjVu-documents with Web browsers.

In 1999 there was published a new version of the format DjVu. It was realized the function of combining several images into one file with the possibility of turning over the pages, as well as the application of so-called "hot spots", in fact, is a hyperlink. The following year came the third version of the format DjVu. About the same time, AT & T sold its development company LizardTech, which began to use it in their commercial products. In this case the format is open. And so today there are many free software to work with him.

By itself, the format DjVu is a very interesting solution, which is a technology image compression losses. Its essence is to split the document into three layers: the foreground, background and black and white mask. Each of them is treated differently. This uses a number of different technologies: an algorithm to separate text from background in scanned images, wavelet compression background IW44, the compression of black and white images JB2, a universal compression algorithm for ZP, the algorithm of unpacking on request. This approach allows to achieve maximum compression with minimal distortion. A scanned page from the book is in DjVu format volume of 10-25 kilobytes.

A few words about PDF

For the first time on the format of PDF (Portable Document Format) public hearing in 1991. That's when the company Adobe Systems has announced its new technology as the electronic submission of any printed products. Novelty turned out very successful. The following year the PDF format has received the prize at the prestigious international exhibition Comdex Fall. The company Adobe Systems has paid much attention to the development of its design. In the 1994 launch of version 1.1 of PDF, which was implemented support for external links, machine-independent color flow of articles and commentaries, and some functions related to security. The next version of the reporting format appeared in 1996. It has been supports OPI 1.3 specifications and color space to CMYK.

Format PDF 1.3 was released in 1999. He differed from his predecessor's support of 2-byte CID fonts, specifications OPI 2.0, the presence of technology smoothing shadows and gradients. The next version of the reporting format was published in 2001. It appeared important functions such as support for transparency, 128-bit encryption, the ability to install the print quality. And, finally, the last for today is version 1.7 of PDF, which appeared in 2006.

The main difference between the PDF format is widely disseminated. Today, in this format are available many manuals, technical documentation, periodical press and other kinds of documents. And almost every computer has the software for viewing documents in PDF.

DjVu and PDF: different areas of application

If we talk about using formats DjVu and PDF for the organization of electronic documents, pay attention to the following features of each. The main advantage of the format DjVu - very small file size. He was particularly good at dealing with such documents, in which many unrecognizable items: pictures, diagrams and formulas. Furthermore, DjVu well suited in cases where the need to convey not only the text itself, but it should look like: the color and texture of the carrier, the existing flaws in it and the traces left by other objects. Thus, DjVu is perfect for storage of technical documentation, for example, instructions and manuals, as well as historical and just as rare documents. Today in the global network are vast libraries of all kinds of literature, which is written in this format.

However, note that each time speaking about the files in the format DjVu, we mention the scanning of real on paper or other media documents. And this is no accident. This format was originally created to store the name of the scanned copies of documents. Today almost no tools, and the need to create DjVu-files as something else.

Disadvantages to the use of the DjVu image format electronic document circulation, a lot. First, it uses data compression with losses. And it is not very good when it comes to treaties, acts, and other legally binding documents. Secondly, the relatively small spread of the DjVu image format does not allow companies to freely use it to exchange information with their partners or customers. The vast majority of both corporate and home computers simply no software to view these electronic documents. Thirdly, in this format completely absent at least some means to ensure the security and confidentiality of documents.

The format of PDF, it is more suitable for the organization of electronic documents. The most important thing - is it widely. As we have said, virtually every PC, regardless of use on it the operating system installed software that allows you not only read the PDF-document, but also to "materialize" it on any printer. And it is in the form in which it is created the owner. Thus, eliminating the problem of compatibility of formats - one of the most serious problems in the organization of electronic documents.

The second advantage of PDF is a built-in protection against unauthorized access. With its help, you can protect your document from any view or unauthorized use. As the protection of cryptographic technology is used repeatedly tested as software developers and experts in the field of information security.

And, finally, the third advantage of PDF is its standardization organization ISO (International Organization for Standardization). At the moment this format already has the status of a standard for storage of archival documents and exchange of information by companies in electronic form. And this is only the beginning. Developers are going to allocate it to the format specification of the NGO Association for Information and Image Management. In this case, there is a high probability that the PDF will become an international standard for the organization of electronic documents.

What conclusion can we draw from all of the above? It turns formats DjVu and PDF can not be considered rivals. They are designed for different tasks, and therefore do not compete but complement each other. As the basis of an electronic document management is better to take, of course, to PDF, which, de facto, became the worldwide standard. It should be noted that some companies are already digital DjVu-technical archives and other documents created by scanning paper documents. However, this is not a reason for choosing this format. It is better to build a modern, a working system of electronic document and existing DjVu-files simply convert to PDF.

Convert documents from DjVu to PDF

To implement electronic document management systems is usually used to work with files selected format software, including, and distributed free of charge. But there is one problem with which such software can not cope. It is about converting documents from the DjVu image format into PDF. To solve this problem we have to use additional software, for example, Universal Document Converter. This universal product for converting documents into different formats, which is perfect in our case.

According to the principle of the program Universal Document Converter is virtual printer. During installation, it creates an additional operating system printer, available in any software. In publishing this printer, the user receives the output file for each format. This approach is most useful in practice. First, it allows the conversion process quickly, with little preliminary work. Secondly, it is so simple that it requires no training of end users.

Algorithm to convert DjVu file format in PDF-document by using the Universal Document Converter is as follows. First, the user must open the file DjVu. You can do this in Internet Explorer pre-installed with a special plug-in. After that, he can only click on the Print button and select a printer Universal Document Converter.

Marat Davlethanov
By order fCoder Group, Inc.