Logo von is a German website on legibility and has so far only been partially translated into English. Two interactive tools, however, are available in English and can be used to calculate precise font sizes and colour values for specific applications:

Below, you can find more information on the background, concept and development of Please note that most of the links refer you to German-language websites for now. addresses communication design for people with and without visual impairments. The individual prerequisites that people bring as readers result in different demands on the design of fonts, texts and images, the quality and properties of print media and the design and usability of digital media. Various concepts for meeting these demands already exist under the headings of Accessibility, Universal Design and Design for All, but there are few concrete recommendations for communication designers. Advice on readable design is dispersed throughout specialist literature on the topic and can be found in other sources, in particular in the German Institute for Standardization (Deutsches Institut für Normung) DIN 1450 standard on legibility, which was updated in 2013. Such standards however, hold little appeal for most designers, so we have collated the existing knowledge in this area and divided it into five sections:

Our recommendations were developed within »Inklusives Design« project of the German Federation of the Blind and Partially Sighted (DBSV) and have been evaluated by specialists in the fields of typography and visual impairment. We now offer specific, practical and useful tools for designers, media designers and interested members of the general public. We explain technical backgrounds and provide sources for further details. Two interactive tools, the Font size calculator und Contrast calculator, can be used to calculate precise dimensions and colour values for specific applications.

Many of the factors listed above apply across a range of different media, so we do not differentiate between printed materials and digital media. For the latter we offer further tips and follow-up links in the chapter on »Digital Media«.

Human perception is complex, technologies constantly changing, the sources are comprehensive and confusing, and many questions are still open, so these recommendations reflect only the current state of knowledge. It is still imperative to review and scrutinize each design and new findings will increase our knowledge in this area. The authors will be happy to receive any technical advice and comments.


Editorial information

Florian Adler, Tim de Gruisbourne and Claudine Stolzenburg
(adlerschmidt gmbh kommunikationsdesign)

Hilke Groenewold, Volker Lenk and Sabine Richter
(Deutscher Blinden- and Sehbehindertenverband)

The concept for the »« Internet platform was developed as part of the »Inklusives Design« project.

We would like to thank Albert-Jan Pool for his expert advice, Prof. Axel Stockmar for his technical advice on implementing the Contrast calculator, and all the authors of the sources and specialist literature cited.

Design and Code

Florian Adler, Tim de Gruisbourne, Claudine Stolzenburg, Björn Barnekow und Arik Hohmeyer
(adlerschmidt gmbh kommunikationsdesign)

An offer of the
Logo vom Deutschen Blinden- und Sehbehindertenverband e.V.
Developed in cooperation with
Logo of adlerschmidt GmbH kommunikationsdesign

Supported by Aktion Mensch