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?

Christmas dinner with Roboy

What really is Artificial Intelligence?
What is the definition of intelligence at all?


With a height of just 140 cm Roboy seems to be a nice guy. Surprisingly, he is capable of showing emotions and thus shows visitors that even androids "have a heart". Well, not really, but its "angry mode" was quite funny. Should we consider this artificial intelligence (AI), or just a nice feature coded into the control center of this imitation of a human body?

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?