Despite the increasing availability of internet access, the printed telephone directory is still as relevant today as it was twenty years ago. People still leaf through the pages to find a number, or possibly an address, easily and quickly. A well-executed telephone directory is one of the best examples of functional information design.
To more closely integrate the directory business into the visual identity of the rest of the company, British Telecom (BT) decided in 2004 to update its telephone directories with a new page layout, including a specialist adaptation of the BT Sans brand fonts we designed for them in 1999. The brief was simple: maintain the brand expression of the directory-adapted fonts, ensure the highest legibility at 5.5pt font size with 5pt leading in two styles, Regular and Bold, and together with the page layout changes, achieve significent space savings.
The directory already had strong functionality before the redesign, so our senior designer Ron Carpenter undertook extensive studies to evaluate the existing type, a variation of Bell Gothic originally designed in the late 1930s for AT&T, and to define the parameters for our BT Directory font. The small font size and its condensed nature necessitate enlarging the x-height to retain clarity and legibility, and at the same time, ascenders and descenders need to be kept relatively short to facilitate the tight leading required. Our findings also showed that BT's previous directory font, in the tradition of Bell Gothic, contained strong ink traps – angled cut-outs in tight junctions which were traditionally designed into hot metal type at small sizes to prevent the sticky ink from filling in tight corners.
Despite already knowing that the contrast of Regular and Bold in the existing fonts was successful, we provided Design House, the design agency working on the layouts, with an extensive series of weight and width tests. All of the test fonts were used in a dummy layout and test printed at BT's directory printworks. Looking at the proofs we were astonished by the quality of the print – where we thought ink trapping would be necessary we found that even the smallest counter spaces were clearly defined in both of the print processes used for BT's directories.
Seeing that the print was of such high quality allowed us to be more subtle with the design of the characters and the overall brand expression. Throughout the design process we submitted the font for repeated testing and refinement, including testing to ensure that the font was as accessible as possible considering that directories are used by any age group, from eight to eighty, until we arrived at the design that is currently used throughout the UK.
A test of the new font showed that without even changing the page layout we were able to save on average ten lines per page. Multiplied by 300 pages per directory, multiplied by 25 Million books printed per annum, the result for BT was a cost saving over just one print run that was larger than the cost of developing the new fonts. The BT directory is an excellent example how font design not only enhances brand continuity but also has the capacity to save money and reduce environmental impact.
