Using native applications in a PDF document conversion service

Automated conversion of Office documents into PDFs has become a popular service. When designing the architecture of such a service, the question arises as to whether the native application or a specially developed software library should carry out the conversion. The pros and cons are not obvious, so it's worth taking a closer look.

If high quality rendering is required then using the native application is a must. This is especially true for the Microsoft Office products. Alternatives such as LibreOffice or software libraries show some major flaws in the visual representation. A typical example is hidden content, which results from a faulty resolution of transparent objects. Also, if columns are rendered left-justified rather than right-justified, legibility of numbers can be difficult.

Software libraries for format conversion are usually easy to integrate and operate. On the other hand, it is not trivial to use the native applications for an automated conversion process, as they were designed primarily for interactive use. Although many of these applications can be controlled remotely via a program interface, they have some special characteristics that must be taken into consideration. For example, the user-specific configuration of the application influences the conversion process. Or, suddenly pop-up windows appear that need to be pressed. Most of these applications must also run in a user session and can not be run in the context of a service. Furthermore, many of these applications are not suitable for mass processing and must be regularly monitored and restarted.

Although many of the native applications today have a "save as PDF/A" feature, the generated files lack fidelity or do not conform to the PDF/A standard. Therefore, in many cases it is better if the service first generates a normal PDF file and then converts it to PDF/A. In some cases a "Save as ..." function for normal PDF files is not available at all. In these cases, a specialized printer driver must be used, which ensures that a flawless rendering via the print function can be done.

It pays to use native applications for the conversion service. Ultimately, the resulting quality of the generated documents is what the user sees. However, the better quality has its price: the conversion service has to master all the challenges. Simpler and cheaper products usually opt for the use of conversion libraries. Only products in the highest league are able to meet the high quality requirements of the rendered documents.