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.
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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?
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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.
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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, ...
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TIFF Mixed Raster Content (MRC) conforming to RFC 2301
Mixed Raster Content (MRC) is a process to reduce the size of raster images. It is well known since PDF/A is used to archive scanned documents. However, it has been used and standardized in RFC 2301 for TIFF files earlie ...
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Stroking geometric paths - not as easy as it seems
In PDF geometric paths are simply described as lines and cubic bézier curves. The filling of a path is straight forward once one understands the even-odd and non-zero-winding rule. The stroking of a path however is not a ...
Tech corner
PDF transparency reviewed
This new blog thread is dedicated to the development of the PDF standard and its associated sub-standards. As a delegate of the Swiss Standardization Association (SNV) in the ISO Comittee I'm supposed to review all relat ...