Information & Links
Vischeck is based on SCIELAB
from the Wandell
lab at Stanford university.
The dichromat simulation code is from an algorithm described by
Francoise Vienot and
in a paper which appeared in the
Journal of the Optical Society of America V14, #10 pp2647.
see also: pubmed)
Much of the pre- and post-processing of the images utilizes
ImageMagick, a freely available
image processing package.
A nice primer on human color vision can be found at Clive Maxfield's site.
Color blindness is described in more detail in various places on the web.
Try a search in Google.
A recent, well-researched addition with plenty of nice graphical examples
can be found at this
site. There's an interesting list of frequently asked questions
(including a good discussion of whether you can 'cure' color blindness) on
Terrace L. Waggoner's site.
Various other visual disorders are described and simulated at
site from Brian Thomas Wagner and Donald Kline at the University of Calgary.
Graphic design and accessibility
There are many resources on human interface design on the web. One of our
favourites is Jacob
Masataka Okabe and Kei Ito have put together an
on how to make scientific presentations more accessible to people with
has written some informative and useful articles about accessibility,
including a nice discussion of the use of fonts in HTML. Nick Clark
has put together an excellent resource for general accessibility
issues at his CurbCuts site.
Chuck Newman has an excellent feature
on his site that is complementary to Vischeck.
He also has a colorblind survey
that you may consider filling out.
An excellent treatment of web site design for colour-impaired users comes from British
Compensating for Color Deficits
While there is no known cure for color blindness, there are some tricks that
individuals with a color deficit can employ to help distinguish colors. For
example, color filters can often be helpful (e.g.
SeeKey). Some individuals also report
using different illuminants to distinguish colors (e.g., examine a fabric
under a store's florescent lighting and then move to a window and examine it
Tools like WhatColor might be useful
for identifying colors on a computer display.
More general resources for vision include
the VisionScience website,
'The Joy of Visual
Perception', and WebVision.
ColorMatters has a nice site with lots
of information on color.
Good, general books on color and vision are hard to find. For an overview of the whole subject we recommend
Colour Art and Science (The Darwin College Lectures)
edited by Trevor Lamb and Janine Bourriau.
This is a very readable collection of essays on color that cover the biology of color and color vision
and also touch on some of the more philosophical aspects of human color perception.
Naturally, we also have to recommend Foundations of Vision by
Brian A. Wandell. Although this
is less accessible to the layperson, it will appeal to those looking for a solid, engineering approach to
the study of vision. It includes chapters on color vision and pattern sensitivity which are at the heart of
the Vischeck engine.
An excellent introduction to color blindness is
Color Blindness by Donald McIntyre. It contains a large amount of useful technical information as well as some enjoyable facts (for example, did you know that people once thought that injecting cobra venom and 'lobster extract' into the eyeball was a good way to cure color blindness?). More information is available on the author's website: www.daltonism.org.uk.
A more technical reference is
Diagnosis of Defective Colour Vision by Jennifer Birch, which describes color blindness from a clinical and diagnostic perspective.
Finally, for a fascinating account of a color deficit that affects an entire population, try Oliver Sacks' book
The Island of the Colorblind. In it, he describes a journey he made in the mid 1990s to a remote island
in Micronesia where a large proportion of the people develop a condition known as 'rod monochromatism' and have no color vision at all. His account of the visit is sympathetic, educational and surprisingly entertaining.
General Optometric Resources
The American Optometric Association (AOA) is an alliance between student, state, and military optometric associations that was founded in 1898. They set professional standards, provide education and conduct research into quality vision care. The AOA website is a useful resource for general questions about eye care.