The Effects of Contrast and Density on Visual Web Search
http://psychology.wichita.edu/surl/usabilitynews/62/density.htm

Weller, Donnelle
Usability News
2004

Abstract:

This study evaluated the effects of white space on visual search time. Participants were required to search for a target word on a web page with different levels of white space, measured by level of text density. Screens were formatted with one of four types of graphical manipulation, including: no graphics, contrast, borders and contrast with borders under two levels of overall density and three levels of local density. Results show that search times were longer with increased overall density but significant differences were not found between levels of local density. Only the use of contrast was found to be significant, resulting in an increase in search time.