Forbidden colors, as defined by color vision theories, are colors that humans cannot perceive under normal circumstances because they are outside the typical spectrum of visual experience. These colors are not "impossible" but rather do not fit within the standard way our brain processes color information.
The Concept of Visual Opponency
The idea of forbidden colors arises from the theory of visual opponency. This theory suggests that our vision processes color as pairs of opposites:
- Red vs. Green: We see a color as either reddish or greenish, but not both at the same time.
- Yellow vs. Blue: Similarly, we see a color as either yellowish or bluish, but not both simultaneously.
Examples of Forbidden Colors
Based on visual opponency, the primary examples of forbidden colors are:
- Reddish Green: A color that is simultaneously red and green.
- Yellowish Blue: A color that is simultaneously yellow and blue.
Why are they "Forbidden"?
Our visual system is wired in a way that processes colors along the red-green and yellow-blue axes. We interpret colors as falling somewhere along each axis. Therefore, colors that would need to be both red and green or both yellow and blue are not easily processed by our brain, making them appear to be "forbidden."
Experiencing Forbidden Colors
While these colors are considered forbidden for normal perception, there are exceptions. As the reference states, people can experience these colors through hallucinations. This shows that the processing mechanisms in our brains, under unusual conditions, can generate experiences beyond the typical spectrum of color vision. These hallucinations provide a window into the workings of visual opponency and demonstrate that the perceived limitations on color vision can be bypassed.
Summary
In summary, forbidden colors, such as reddish green and yellowish blue, are not seen in everyday experience because our visual system processes colors through opposing pairs, making combinations like “red and green simultaneously” or “yellow and blue simultaneously” non-existent to our normal perception. However, these colors can be experienced in atypical states like hallucinations, which help us understand more about how color vision works.
