Effect of Visual Adaptation Upon Intensity of Illumination Preferred for Reading With Direct Lighting

• 成果类型: Article
• 署名作者: Tinker, Miles A.
• 刊物名称: JOURNAL OF APPLIED PSYCHOLOGY
• ISSN/ISSBN: 0021-9010
• DOI: 10.1037/h0053483
• 发表日期: 1945
• 页码: 471-476

摘要

The author surveys the literature to indicate that individuals express a wide range of preference for intensities of illumination as best for comfortable reading under general lighting. Failure to allow for adaptation between changes in intensities has been a common fault in many a previous study. Visual adaptation at the time of choice seems to play a large role in determining individual intensity preferences. The scope of the present report is narrow, being concerned with the effect of visual adaptation upon intensities preferred under direct lighting which is strictly local. 60 university students entered a light laboratory with no outside windows. The illumination was derived from standard, metal-shade, flexible-arm, reading, desk lamps equipped with frosted bulbs. Illumination available ranged from 4 to 100 foot-candles. The subjects observed at 2 sittings: one adapted to 20 foot -candles; the other at 50 foot-candles. After each adaptation (15 min.), each subject chose between the standard to which he was adapted and each of 5 other intensities on the basis of intensity preferred for easy, comfortable reading. The subject was readapted to the standard for 2 mins. between each comparison of intensities. There was a 10-inch, uniform spot of illumination on the reading stand. From the perimeter of this area outward, intensity of illumination decreased rapidly. The reading text was printed in 11 point type with 2 point leading and a 23 pica line width on mat white paper. Visual adaptation at the time of choice influenced preference only slightly. There was a marked tendency to prefer intensities at and above the brightness to which the subject was adapted resulting in frequent choice of high intensities. With the direct lighting used here, these preferred bright intensities have unfortunate implications for the hygiene of vision. They are the very factors leading to rapid visual fatigue. Hence, subjective, intensity-preference reports yield unsatisfactory data for prescribing lighting for individual reading.