Document Detail

Psychophysics of reading. XI. Comparing color contrast and luminance contrast.
MedLine Citation:
PMID:  2231110     Owner:  NLM     Status:  MEDLINE    
Text can be depicted by luminance contrast (i.e., differences in luminance between characters and background) or by color contrast (i.e., differences in chromaticity). We used a psychophysical method to measure the reading speeds of eight normal and ten low-vision subjects for text displayed on a color monitor. Reading speed was measured as a function of luminance contrast, color contrast (derived from mixtures of red and green), and combinations of the two. When color contrast is high, normal subjects can read as rapidly as with high luminance contrast (greater than 300 words/min). Curves of reading speed versus contrast have the same shape for the two forms of contrast and are superimposed when contrast is measured in multiples of a threshold value. When both color and luminance contrast are present, there is no sign of additive interaction, and performance is determined by the form of contrast yielding the highest reading rate. Our findings suggest that color contrast and luminance contrast are coded in similar ways in the visual system but that the neural signals used in letter recognition are carried by different pathways for color and luminance. We found no advantages of color contrast for low-vision reading. For text composed of 6 degrees characters, all low-vision subjects read better with luminance contrast than with color contrast.
G E Legge; D H Parish; A Luebker; L H Wurm
Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Journal of the Optical Society of America. A, Optics and image science     Volume:  7     ISSN:  0740-3232     ISO Abbreviation:  J Opt Soc Am A     Publication Date:  1990 Oct 
Date Detail:
Created Date:  1990-12-07     Completed Date:  1990-12-07     Revised Date:  2007-11-14    
Medline Journal Info:
Nlm Unique ID:  8402086     Medline TA:  J Opt Soc Am A     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  2002-10     Citation Subset:  IM    
Minnesota Laboratory for Low-Vision Research, University of Minnesota, Minneapolis 55455.
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MeSH Terms
Color Perception / physiology*
Contrast Sensitivity / physiology*
Middle Aged
Vision, Low / physiopathology
Grant Support

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