高齡者對PDA彩色文字之視認度研究

Legibility of Text-Color Combinations of PDA for the Elderly

以PDA螢幕為研究載具，探討高齡者對彩色文字之視認度為本研究的目的。本研究針對65歲以上的40位高齡者（71±5.5歲）與40位年輕族群（24.5±2.8歲），進行不同文字色與背景色的色彩組合，與字級大小之文字視認度的實驗。以HSB色光系統為依據，選用的色彩之色相值分別為0、30、60、90、120、150、180、210、240、270、300、330（彩度與亮度值皆設定為100），與無彩度的黑色、白色，共計14種顏色。文字則選擇常用的6 筆畫的細明體，共45字；字級從8pt至16pt共9種，作為實驗用字。從研究結果得知，受測族群與字級大小對文字的視認度具有顯著性的影響。尤其在色相為紅色（H值＝0）、綠色（H值＝120）、藍色（H值＝240）與其相鄰的色彩作為PDA彩色文字的視認度趨近於零。另一方面，色相值從30至180的色彩範圍，其文字與背景的色彩組合的平均視認錯誤率比其他範圍高；同時在此範圍的色彩組合，高齡族群比年輕族群有較明顯的高視認錯誤率。整體而言，文字與其背景的色彩組合之視認度，與其舒適度的主觀評價具有一致性的變化趨勢。從高齡者的觀點，排除紅色、綠色、藍色與其相鄰的色彩組合，當字級為12pt之六筆畫的中文細明體字，應可滿足PDA彩色文字之通用設計的需求，使全體使用者的平均視認錯誤率降至10%以下。

This study aimed to investigate the legibility of text-color combinations of a personal digital assistant （PDA） for the elderly. Forty elderly people （71±5.5 years） participated as subjects and forty young people （24.5±2.8 years） were enrolled as the control group. All participants had to read texts of different colors and sizes on the PDA. Fourteen colors, including white and black, were used as text or background colors. Font sizes used ranged from 8 to 16 points. The number of texts misread by the subjects was recorded. Our experimental results reveal that texts in red, green or blue with similar shaded adjacent colors as backgrounds were hardly legible to subjects of both age groups. Using hues ranging from 30 to 180 of the HSB color system results in higher error rates than texts in hues of other ranges （210-330） as well as more misread texts for the elderly than the young controls. There was a significant positive relationship between the legibility of text-color combinations and the comfort value of subjective estimation. For a universal PDA design that can cater for both the elderly and the young, red, green or blue with similar shaded color as backgrounds should be avoided, while Chinese characters in Thin Ming style of six strokes and font size 12 should be used, thus keeping the average misread errors to under 10%.