The Effects of Character Size, Modulation, Polarity, and Font on Reading and Search Performance in Matrix-Addressable Displays

This research is the second in a series of experiments undertaken to develop optimum design criteria for matrix-addressable displays. This study examined the effects of character size, luminance modulation, font, and polarity on both contextual task (reading) performance and performance in a random search task. The random search task consisted of locating a target letter or numerical within one of nine sectors on the display. Only upper case alphabetic characters and the numerals 0 through 9 were used. Using a font (3) by modulation (3) by polarity (2) by character size (3) within-subjects factorial design, only the main effects of character size, font, and polarity were found to be significant. There were no significant interactions. Post hoc analyses indicated that response speed increased as character size increased from a 7 x 9 matrix, to a 9 x 11 matrix, to an 11 x 15 matrix. Post hoc analyses revealed that response times were longest with the maximum dot font, but did not significantly differ between the Huddleston and Lincoln/MITRE fonts. Additional post hoc comparisons indicated that negative contrast (dark characters on a light background) produced significantly faster response times than did positive contrast (light characters on a dark background).