This paper describes how warnings and other text are useless if they cannot be read. Restricted to black and white, the legibility of warnings is primarily a matter of letter size and letter contrast against some background. Other geometric characteristics of the letters, including height-to-width ratio, stroke width, and spacing between letters also affect legibility. Though the effects of subtler font characteristics are not fully understood, the basic requirements are well established. However, the resulting recommendations for good legibility refer only to text in black and white. Technology has made color ubiquitous in printed and electronic display media and evidence is ample that color can attract attention, organize and improve recognition accuracy of the information presented in print and pictures. However, no standard for the legibility of colored text or the visual effectiveness of colored graphics have been developed.
Abstract