How to process device specific colors in PDF

The chapter about rendering in the PDF standard specifies how to transform colors from one device specific color space to another and gives hints on how to transform calibrated colors to device specific colors. But most implementations ignore those rules and use ICC profiles to characterize the output devices. But, what does this mean for the black-generation, the undercolor-removal and other functions in the graphics state?

A best practice for using output intents

Output intents describe the characteristics of the device on which a document is intended to be rendered. Traditionally, the target device is a printer. But, how about display monitors?

Embedding fonts in PDF - a never ending struggle

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, however, is related to fonts. But, why does dealing with fonts in PDF files turn out to be so troublesome?

How to create tagged PDF/A from Microsoft Word documents with decent quality

Microsoft Word offers an add-in to save a document as a PDF/A file. Good to hear, I thought. I ran the output through the PDF Validator for a standards conformance check. No complaints. That's great, isn't it. So, I shed an eye on the visual quality. Oops! To my surprise some content is depicted as a black rectangle instead of showing a nice drawing.

Utility to simplify the import of certificates and private keys into a PKCS#11 cryptographic token (HSM)

The 3-Heights™ Security API supports the creation and verification of digital signatures using a cryptographic token via a PKCS#11 interface. However, the component can only be used if the token has appropriate certificates and private keys stored on it. A useful command line utility helps to store the required objects into the token.

Do the PDF scan conversion rules have an impact on anti-aliasing?

The scan conversion rules in PDF are special in the sense that none of the publically available graphics libraries implements them. On the other side almost every PDF rendering engine implements an anti-aliasing mechanism to support low and medium resolution bitmaps. The question that immediately arieses is: how do these two mechanisms relate to each other?

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 earlier.

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 as simple as it seems at the first glance. Let us have a look into stroking and some special cases.

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 related working documents. Currently I'm focussing on the working draft of the new ISO Standard ISO 32'000-2 (PDF 2.0), especially the chapter about transparency.

Controlling enveloping machines using OMR markers

In this new blog thread I'd like to inform you about new features and applications of our tools. Enveloping machines can be magically controlled with these tiny dashes called OMR markers on the border of a printed sheet. But how can I easily create them?