Dealing with error messages in PDF Converter when working with edited PostScript files

Please note that when you run PDF Converter and see a PostScript error, that doesn’t necessarily mean that you have found a bug in PDF Converter, any more than an error in compiling a program means that there is a bug in Microsoft Visual Studio.

You might have a problem instead with your PostScript source content.

PostScript is a Turing complete language. This means that it can simulate any Turing machine, or, effectively, it can be used to execute any computer algorithm. This does not apply to PDF or Hewlett Packard PCL printing language.

PostScript files are nearly always generated by software applications that assume that the .ps output file will be sent to a PostScript-enabled output device, generally a printer. PostScript is not meant to be device specific, but commonly PostScript files are generated with a specific printer or class of printer devices in mind. As a result PostScript files are meant to be processed with a linear parsing model— page 1, page 2, page 3–with the content for each page set. The system generating the PostScript file commonly is not designed to allow for content in the PostScript file to be edited or moved after the file is produced. That level of code sophistication isn’t needed, because the presumed target for the PostScript file output is already known. The PostScript file is intended to work with that output device or set of output devices.

But a software tool that filters PostScript content after the PostScript file is generated, or adjusts the order of objects on pages in that PostScript file, frequently introduces errors in the file. This kind of post processing can render an edited PostScript file that PDF Converter will not be able to process properly. You might see other products that can “work” successfully with the same corrupted PostScript file, but that is likely because the other product lacks features found in Adobe PDF Converter. For example, one popular PostScript and PDF language interpreter does not provide support for forms, though PDF Converter does. As a result this interpreter is likely to simply position form content on a page without regard to the form layout in the original content. So a PostScript file edited and processed using this product might complete without showing any errors, but if the same file is used in PDF Converter, it will fail.

Imagine, as an analogy, that you wrote a C# file for a Mac machine and then sought to use a conversion tool to reprocess it so that it would work in a Windows environment. Then, you sought to compile that file using GCC. You wouldn’t assume that there was a bug in GCC if the compiler rejected the program file. Likewise, taking a PostScript file that is device specific and converting it to device independent is likely to corrupt the PostScript file in ways that PDF Converter will not be able to correct.