The Young-Helmholtz Theory of Color

The Young-Helmholtz theory of color discusses the human eye's photoreceptors.

The Young-Helmholtz theory of color was developed in the 1800s by scientists Thomas Young and Hermann von Helmholtz. Young and Helmholtz did not work together, but Helmholtz adapted Young's earlier theory. They determined that the human eye uses "trichromatic color vision" or that there are three different types of cells to discern color.

Thomas Young's Findings

In the early 19th century, Thomas Young hypothesized that the eye must have different types of cells, known as cones, that sense different wavelengths of light .

Helmholtz's Development of the Theory

Hermann von Helmholtz later modified the theory, finding that there are three types of cones that sense light. Helmholtz found that people could see any color by mixing just three wavelengths of light: violet, red and green.

Wavelengths

In the theory, blue is known as a short wavelength, yellow is a medium wavelength and red is a long wavelength.

Cones

The theory states that the human eye has specific types of cones optimized to each of these wavelengths, which is what allows us to see a full range of color.

Mechanics of Color Vision

According to the theory, colors stimulate one, two or all of the cone cell types, allowing discernment of color. For instance, the color "orange" would activate the medium-wavelength and long-wavelength cones.

References

• "Biological Psychology"; J.W. Kalat; 2009