Color vision is an attribute of the human perceptual array that perhaps developed in order to aide in survival. The ability to distinguish colors has long been an asset in finding food, avoiding predators and enjoying the beauty in the environment. As long as man has had the ability to see the world in color, the question ìhowî has been asked (Color, 2002).
In ancient Greece, Empedocles was close to being correct with a four-color doctrine based on the colors black, white, yellow-green and red. In the Middle Ages, a man named Alhazen said that vision is a passive experience. During the Renaissance several people proposed new ideas. Leonardo da Vinci favored a three-color theory over the four colors of Empedocles (Crone, R.A. 1999). He also replaced the yellow-green with plain yellow. During this same period, Johannes Kepler posed the question of whether or not we see with the eyes or with the brain. At the close of the Renaissance, there was a scientific revolution which involved great minds such as Kepler, Galileo, Descartes, and Newton.
Finally, in the early 1800s, a man named Thomas Young developed a theory based on some color matching experiments that stated that color vision is dependent on three cone types in the eye and the wavelengths that they respond to (Padgham & Saunders 1975). Hermann von Helmholtz agreed with this theory and supported it through his own work. Basically, the procedure for the color matching experiments done by Young and Helmholtz started by finding participants with normal color vision. The participants were then asked to adjust three wavelengths to match the color of a single wavelength. Since it was possible to match the color exactly with three wavelengths (Motokawa, 1970), it was concluded that the eye must have three receptor types. A different wavelength grouping activates each type. There are cones for short wavelengths such as blues and violets, the medium wavelengths like the greens, and the long wavelengths like reds and yellows.
In the 1960s, Scientists discovered that there were three different types of cones in the human eye. They had maximum absorption at 419 nm in short wavelengths, 531 nm in the middle wavelengths, and 558 in the long wavelengths (Goldstein 2002).
Color vision is possible with only two receptor types; however, a reduced number of colors can be seen. This is called color deficiency (Neitz Color Vision Lab 2002). With only one active cone type, it is not possible to see color differences, only varying shades of the same color. There are three types of color deficient people. Protanopia, which affects about 1.02 percent of people, allows vision of shorter wavelengths such as blue and long wavelengths as yellow. Deuteranopia affects about 1.01 percent of the population and works almost the same as protanopia, but has a neutral point of 498 nm instead of 492 nm. Tritanopia is the most rare, affecting about .003 percent of the population. They see blue as short wavelengths and red as long wavelengths and have a neutral point of 570 nm (Goldstein, 2002).
Even though people with color deficits make up a small number of the population, they should be considered in the design of everyday materials whose recognition depends on color. Many people have to learn to deal with this delimma. There are several social and occupational implications of defective color vision (Color Blindness or Color Deficiency 2002). Artists must be able to distinguish the colors they are using or they must adapt. One artist went so far as to use only black and white paints. Electricians must be able to distinguish color so that they can avoid electrocuting themselves. Police officers must be able to give descriptions of people and cars using the color of paint or clothes. Several other jobs rely heavily on the ability to discern different colors. The loss of color diminishes the pleasure of our everyday lives. Even though at times it seems color is a luxury rather than a necessity (Delman. 2001), perhaps, even for the unskilled laborer, the ability to perceive color would improve the quality of life.
The inability to distinguish business signs would make identifying advertisements much more difficult. Since business signs often rely on color to distinguish them from other signs, I propose an experiment designed to test the colors used on signs. I eventually hope to find new colors for those signs which will put color deficit people on even ground with those who have normal trichromatic vision without decreasing the visibility of the signs for anyone. Some signs, which involve red and blue color schemes or white and yellow color schemes are difficult to read.
Over a one-year period, eighty (80) people will be solicited, twenty (20) people with normal color vision and twenty (20) of each type of color defiecient person. All must have 20/20 or corrected 20/20 vision.
In an attempt to reduce variables such as time of day and lighting conditions, an indoor-lighted range will be constructed. The Building will have dimensions roughly the length of a football field, 110 yards, and the width of a normal house, or about fifty (50) feet. Inside the building will be fifteen (15) lanes, similar to those in a shooting gallery which will have markers at 25, 50 and 100 yards. Each lane will be walled off and individually lighted. There will also be a briefing room and an office. All information will be stored on a computer and 3.5-inch floppy disks as back up. Also, the five types of colr schemes most difficult to distinguish, will be needed. They will be found using another experiment.
The design will be a three by four by five between subjects design. There will be the three distances. There will be the three types of dichromats, plus a control of normal trichromats. Finally, there will be the five different business signs. Each person will view all the signs.
At the beginning of the experiment, the groups will be briefed and asked to sign a disclaimer. Groups will be taken five at a time, as they are found over the five-year period. Everyone will be told that they are free to leave at any time during the experiment and that no psychological damage will occur during this experiment. After the briefing, the groups will be taken to the indoor range and shown the signs in normal indoor lighting from overhead fluorescent lights. They will be taken through the range one at a time and asked to name the fifteen (15) signs, each of the five at three different distances. The first cycle through will be at twenty-five (25) feet. The order of the signs will then be randomly switched up and the second cycle will be at fifty (50) feet. The random placing of the signs will again occur and the participants will be walked through again, this time looking at the signs from one hundred (100) feet away. Each cycle will be videotaped and recorded by a lab technician. The lighting for each group and each cycle is held constant, as is the temperature. After the sign identification tasks, the participants are taken into the front conference room and given paperwork and a contact number so that they can check up on the experiment if they choose to do so. They are then debriefed and given a meal consisting of a sandwich and a cola of their choice for lunch to show them that they and their efforts are appreciated. The results of that group are then saved onto a computer and three (3) back-up copies are made. One is stored in the file cabinet in the office at the range. One is put in my brief case for safe keeping, and the third is taken to a safe deposit box for storage until the data is needed for analysis.
Once all four hundred (400) participants have been run, The data will all be compiled onto a spreadsheet. Means of the information will be calculated and several analysis will be done. First a T test will be run and then an 3x4x5 between subjects Anova will be done. After that, A Pearsons r will be run to see if there is any correlation between the categories. If so, a Tukey test to determine the extent of the correlation will be run.
After the year for this study is up, the trichromatic control group will have distinguished the signs best of all. This follows the hypothesis that because this research is designed only to find a way to bring dichromats up to the level of normal trichromats in the ability to read the signs. Tritanopia sufferers will have most problems distinguishing between signs. Therefore, signs are needed that can be distinguished more by them than the other two. Since there is a noticeable difference in the ability to distinguish the signs depending on ability to see color and the distance, the null hypothesis will have to be rejected and more research will need to be done in order to find signs which will be seen well by all.
Now that it is known how well different business signs can be seen by different color deficient people, several new steps must be taken to further the knowledge base. The first step is to design an experiment which will let a material and a color or series of colors which can be easily seen by all dichromats and all trichromats. Signs will be constructed of varying shapes and use different series of colors depending on their purpose. Hopefully, within a few years of development, the new signs will replace the old style sign and the usefullness of road side advertisement will increase. More research will be conducted at the close of this experiment. Hopefully, using some combination of colors easily contrasted by dichromats and trichromats alike, a new form of sign can be developed that possible will light up the words to give them greater contrast, or reflective paint can be used to cause the meaning of the sign to stand out more prominently. Perhaps, like the "STOP" sign, an easily discernable shape can be made for each sign type. Perhaps a more drastic degree of separation is needed.
Further into the future, I would like to lead research and development into the design of signs which will make it possible for even monochromats to see easily. Hopefully, within twenty (20) years from the close of this research, a team of professionals will be set to work designing and developing signs which will allow all but the totally blind to see it and know what message it carries.
Color. Retrieved from http://www.colorforum.com/ April 2002.
Color and Color Vision. Retrieved from http://www.yorku.ca/eye/color.htm April 2002.
Color Blindness or Color Deficiency. Retrieved from http://www.allaboutvision.com/conditions/colordeficiency.htm April 2002.
Crone, Robert A. (1999). A History of Color. The Netherlands. Kluwer Academic Publishers.
De Reuck, A. V. S., and Knight, Julie (Ed.). (1965). Colour Vision. Boston. Little Brown and Compan
Delman, Howard Mark. (2001). ìA comparison of visual functions between color-normal and color-deficient observers.î Dissertation Abstracts International: Section B: The Sciences & Engineering, Vol. 62, 3-B.
Goldstein, Bruce E. (2002). ìPercieving colorî Sensation and Perception. Library of Congress. USA.
Motokawa, Koiti. (1970). Physiology of Color and Pattern Vision. Hongo Bunkyo-ku, Tokyo. Igaku Shoin.
Neitz Color Vision Lab. Retrieved from http://www.mcw.edu/cellbio/colorvision/ April 2002.
Padgham, C. A. and Saunders, J.E. (1975). The Perception of Light and color. New York. Academic Press.
Snape, Lindsay T. and Jeagle, H. (2001). ìI used to be color blind. Color Research and Application Vol. 26, 269-272.
The Rods and Cones of the Human Eye. Retrieved from http://hyperphysics.phy-astr.gsu.edu/hbase/vision/rodcone.html April 2002.
Trichromatic Theory. Retrieved from http://www.yorku.ca/eye/trichrom.htm on April 2002.
YOUR TITLE. Retrieved from http://serendip.brynmawr.edu/biology/b103/f01/web2/baird.html April 2002.