Design Problems in Visual Displays. Part I; Classical Factors in the Legibility of Numerals and Capital Letters.

The effects of classical factors, such as symbol geometry, symbol brightness, and brightness contrast, upon the legibility of numerals and capital letters are discussed. Included is a consideration of the literature of the last few decades relevant to the specification of acceptable operator performance criteria which must be met by a given display device. Selected studies are reviewed in detail and referenced. For each study, conclusions are drawn and recommendations are made for display design and application. (Author/LH)