Bell Centennial is a sans-serif typeface in the industrial or grotesque style designed by Matthew Carter in the period 1975–1978.
Printed in the smaller point sizes used in telephone directories, the ink traps are not visible, having done their job; filling in and smoothing out the character stroke.
Bell Centennial is an example of a typeface designed to address a particular need, much like Chauncey H. Griffith's Bell Gothic (AT&T's earlier telephone directory face); Adrian Frutiger's Frutiger, designed for signage at Charles De Gaulle Airport; or Erik Spiekermann's FF Meta Sans commissioned by the Deutsche Bundespost (the German federal post office), but not adopted.
Bell Centennial is only one of several typefaces Carter designed to address specific technical limitations, including CRT Gothic (1974), Video (1977), Georgia (1996), and Verdana (1996).
This nomenclature, while simplifying telephone book setting, perplexed some new users once the typeface family was released for general use by the Linotype foundry.