The Ladd-Franklin Theory, proposed by C.Ladd Franklin in 1891, is a theory of color vision that states that color is the result of a combination of three primary colors. This theory was developed in response to the Young-Helmholtz trichromatic theory, which states that color is the result of the combination of three different types of light. The Ladd-Franklin Theory proposes that color is the result of a combination of three different types of light-sensitive pigments (known as photoreceptors) in the eye.
The three photoreceptors identified by the Ladd-Franklin Theory are the red, green, and blue photoreceptors. These photoreceptors are sensitive to light at certain wavelengths, and when stimulated, they produce a corresponding color. The three photoreceptors interact with each other to create the colors that a person perceives. For example, if the red photoreceptor is stimulated, it will produce a red color. Similarly, if the green photoreceptor is stimulated, it will produce a green color, and if the blue photoreceptor is stimulated, it will produce a blue color. When all three photoreceptors are stimulated simultaneously, a combination of colors is produced and the person perceives a single color.
The Ladd-Franklin Theory has been widely accepted and is used to explain how humans see color. It is also used to explain why some people are color blind. Color blindness occurs when one or more of the photoreceptors do not function correctly and cannot produce the correct color. It is also used to explain why some colors are more easily seen than others. For example, yellow is more easily seen than red because the red photoreceptor is less sensitive to yellow light.
The Ladd-Franklin Theory has been further developed by researchers over the years, and is now considered to be a major part of color vision science. It is a foundation for modern color vision research and is used to explain a variety of color vision phenomena.
References
Kandel, E. R., Schwartz, J. H., & Jessel, T. M. (2000). Principles of neural science (4th ed.). New York: McGraw-Hill.
Ladd-Franklin, C. (1891). The physiology of vision. The American Journal of Psychology, 4(3), 465-485.
Rushton, W. A. H. (1985). Color vision: A study of hue discrimination. New York: Cambridge University Press.
Williams, D. R. (2001). The psychology of color: An introduction. New York: Psychology Press.