Web page designers should pay particular attention to the impact of color on understandability and comprehension.  There are some excellent web sites that directly discuss color design problems that can limit a web site's effectiveness.
 

CAST (2000). “Bobby web site.”  Bobby is a free service provided by CAST “to help Web page authors identify and repair significant barriers to access by individuals with disabilities.”   Founded in 1984 as the Center for Applied Special Technology, CAST is a not-for-profit organization whose mission is to expand educational opportunities for individuals with disabilities through the development and innovative uses of technology.
Retrieved at http://www.cast.org/bobby/

“Colors for the color blind.”  This web site states that its goal is “to furnish a set of color charts to aid the color blind in working with computer colors, most especially on the internet and in web sites.”
Retrieved at http://www.toledo-bend.com/colorblind/index.html

Green, M. (1999). “Basic color and design SBFAQ.” The author’s stated goal is “to educate human factors and other visual design professionals on how, when and why to use color.”
Retrieved at http://www.ergogero.com/FAQ/cfaqhome.html

Morton, J. (2000).  “Color Matters.”  A subsection of this web site is devoted to building understanding and providing technical advice for using color in conjunction with all computer applications and web sites. Color web palettes are provided for web designers.
Retrieved at:  http://www.colormatters.com//comput.html

Morton, J. (2000). “Color logic for web site design,”
Retrieved at: http://www.colorvoodoo.com/cvoodoo5.html

Nakahara, H. (2000).  “What color:  an assistant to colorblinds.”  This is a PC software program that is available to assist color blind persons in identifying colors on their computer screens.
Retrieved at:   http://www.hikarun.com/e/

Vischeck:  the world’s first online color-blindness simulator (2000).  Tiny Eyes, Inc., Menlo Park, California.
Retrieved at http://www.vischeck.com/what.shtml

Waggoner, T.L. (1999).  “What teachers, school nurses, and parents should know about being colorblind.”
Retrieved at http://hometown.aol.com/nocolorvsn/color4.htm

Wilson, D. (1998). “Color vision, color deficiency.”  This is an informative site with detailed examples of web design issues.   Retrieved at: http://www.firelily.com/opinions/color.html

Wolfmaier, T. G. (1999).  “Designing for the color-challenged:  a challenge.”  internetworking, 2, 1.
Retrieved at  http://www.InternetTG.org/newsletter/mar99/accessibility_color_challenged.html