PDF knowledge
Find articles that provide you with practical insight into the world of PDFs. Learn all the ins and outs of PDFs, from the fundamentals to the best practices.
ZUGFeRD – A standard for electronic invoices in PDF/A format
Are you still sending out paper invoices to your business partners? Then you may be part of a dying breed. Although 90 percent of all invoices worldwide are still being sent out by post, experts predict that electronic i ...
Embedding fonts in PDF
I collect bad PDFs since the Reference Manual 1.0 was published in 1993 and today I have recourse to a data base of more than 100'000 real world PDF files with all kinds of faults in them. The vast majority of problems, ...
Why is the extraction of text from a PDF document such a hassle
When I use a text editing tool such as Microsoft Word then it is quite natural that I can select a portion of text and copy it to the clipboard and paste it in to a window of any other tool. Not so with PDF. At least not ...
Splitting and merging pages of PDF documents
Single out pages from a number of input documents and re-arrange them in a set of output documents belongs to the daily routine in a document assembly application. At first glance, this seems to be a clear and understand ...
What is PDF compression and optimization?
Most people agree that PDF compression and optimization have something to do with reducing file size. Sometimes it's about faster rendering. Anyway, compression and optimization is a wide topic and it's certainly worth a ...
The discipline of converting PDF to PDF/A
We all know that the conversion one file format to another is not as easy as one might wish for and can lead to unpleasant surprises. However, it is hardly known that this is the case for the conversion from PDF to PDF/A ...
Can I trust PDF validation software?
If I use validation software from different manufacturers I sometimes get different results. Why can this happen? Does it mean that I can't trust the software? What can I do about it? I hear these and more questions very ...
Automating the conversion of Microsoft Office Documents to PDF/A
A central service to convert Microsoft Office documents to PDF or PDF/A has obvious advantages. The conversion is done on an enterprise wide platform with well defined software versions and conversion process configurati ...
Digital signatures in PDF/A
Digital signatures are still not very widely used and the the knowledge about them is often fuzzy. This article tries to give an overview about this huge and complex topic.
Font subsetting - how it works and when to use
In order to reduce the file size PDF producers use a technique called font subsetting. What does exactly happen with the fonts and what are the consequences?
Image detection in scanned images
Detecting pictures in scanned document pages has many advantages such as better compression rates and the possibility to extract them individually.
How to convert signed documents to PDF/A?
I often get the question whether it is possible to convert digitally signed documents to PDF/A. Because there's no short answer to this I thought it would be helpful to explore the topic a bit into more detail. What tec ...