Creating files in the Portable Document Format or PDF is not difficult. The PDF file format has been defined by the ADOBE company. The PDF file format is in reality a database description language (If interested, read this tutorial ). Don't forget that you may insert hyperlinks in a PDF file. Contrary to a widely held opinion, the PDF format specifications are available to anybody, and it may be used by softwares other than those produced by the ADOBE company, In particular, it may be implemented within non-commercial softwares.

In order to help the MDPI foundation to carry its goal of delivering free online scientific journals, we kindly ask authors to try their best to help us as much as possible. A great way to help us is to create accepted version of papers in the PDF format with the same layout as we are currently using.

The MDPI foundation, in order to help authors who cannot afford to make any financial contribution is offering a publication pathway at no charge, provided the entire layout is achieved by the authors. So that the only thing that remains to be done for the MDPI webmasters would be to include a fully formatted PDF file in our WWW sites. These authors must understand that this condition is strict and that their accepted papers are not going to be published until their PDF files are correct.

We have not tested all the links and software that we list below. So don't hesitate to tell us what does work and what doesn't. Any suggestion or information is most welcome !. ( mail to muguet@ensta.fr )

There are a few free online tools that allow to obtain PDF files :

ADOBE is offering ( yes.. this is true ) to help you create 5 PDF files online for free at this URL . starting from a wide variety of formats such as: Microsoft® Office: Word (.doc), Publisher (.pub), PowerPoint (.ppt), Excel (.xls), Rich Text, Format (.rtf) ; Corel WordPerfect (.wpd); Adobe PostScript® (.ps, .prn), Encapsulated PostScript (.eps) ; HTML pages (.htm, .html, .shtml).

FastPdf is a relatively low cost online conversion service from Word format.

Almost every wordprocessor is able to generate a Postscript file output. Starting from Postcript files, you may generate PDF files (free and for an unlimited number of times... ) at this ps2pdf page. The ps2pdf site is using the ghostscript GPL software.

If you are using a Unix operating system such as the now popular GNU/Linux system, a number of free tools are available :

• Using Open Office is now the best way. Starting with Open Office 1.1, it is possible, in a single click, to export files in pdf format, instead of having to use the printing fonction with a "pdfwriter". Open Office is free, and may use a variety of word processor file formats such as word. ( Free books : "OpenOffice 1.1 L'autre suite bureautique" (700 pages) )
• From Postscript : One may use Ghostscript ( see also ) which is installed by default on almost all Linux distributions. Ghostscript may be invoked also with the command ps2pdf . You may also use KGhostView which features a user interface. Simply print into a pdf file. Another more sophisticated program is PDFCreator ( site français .
• From HTML : One may try html2pdf
• From LaTex : One may try
  • texi2pdf
  • tex2pdf

  One last thing : in order to view your superb creations, you may use xpdf or you can download the Linux reader acroread free from ADOBE.

  
  

In the Microsoft circus, ADOBE ACROBAT is the star of the show, but MS-WORD do need Acrobat to be able to produce pdf files.

If you are rich, the easiest way is to order ACROBAT . This reference tool would cost you about $250. Starting from a wide variety of format, it would convert files into the PDF format. There is a special tutorial to help you convert a Web page to PDF .

• Similar to OpenOffice, StarOffice features a free Education Licensing scheme for student, researcher, staff, or faculty member. You may export pdf files from a variety of word processor file formats such as word. Register, and download it !. This is a most interesting solution.
• If you are running under Windows NT Version 4 Service Pack 3 or higher or Windows 2000 SP 2 or higher you may be able to run OpenOffice ,but the build process is not automated with an installer.
• From Postscript : There is a Ghostscript version for Windows : gs700w32.exe gsv40w32.exe .
• From HTML: there is an html2pdf version for Windows.
• From Microsoft Word, a suggestion is to produce first a postscript file, by printing to a file while selecting a Postscript printer. Then you convert your postscript file into PDF.
• A new software has been proposed recently by a company from the Macromedia group : RoboPDF (Price 79 $). There is a free RoboPDF version : the RoboPDF Home Edition offers users high-quality PDF creation capabilities for personal, at home use. RoboPDF Home Edition is available for in-home use only, and is not legal for commercial or government use.. Download here. Since we are a non-profit operation, we guess it could be used by authors who are preparing all the layout.
• PDF995 is also a software for free ( with advertisements ).

Ghostscript seems the best bet, but there might be other alternative.

There is a version of OpenOffice that is freely available for Mac OS X (X11) . There is also an ACROBAT version for MAC.

Ghostscript is available for a wide variety of OS A port to Mac is available. The porting of OpenOffice is under way for a wide variety of platform.