PDF Association has published the first application note for PDF 2.0. The topic is black point compensation (BPC).
Black point compensation allows control of the color conversion of the darkest color in an image. With BPC activated the darkest color in the source color is mapped to the darkest color in the destination color. This results in a better tonal progression of the darker colors:
Unfortuantely black point compensation is not part of the four rendering intents of the ICC. That’s why Adobe has defined BPC in a TechNote years ago. Since then all relevant vendors have implemented BPC in their products. Today BPC is standardised in ISO 18619:2015.
In PDF 1.x control of color conversion was only possible using the four rendering intents. In PDF 2.x a switch for BPC was added. Each object can have it’s own BPC behavor. This allows e.g. to enable BPC for images and disable BPC for critical colors (e.g. logos).
At the moment it’s not clear where this switch will be defined:
- in the image processing application?
- in the layout application?
- in Acrobat?
- with an Acrobat plug-in
- with preflight fixups
The application notes of PDF Association want to explain the new features to the developers and therefore help creating useful implementations. Let’s hope the best… 😉