- The human eye doesn’t truly perceive purple because it’s not present within the visible light spectrum.
- Purple is created by combining wavelengths from opposite ends of the color spectrum, which technically It doesn't make any sense, but our brains developed a workaround.
- When our eyes perceive a mix of blue and red wavelengths, the brain forms a circular continuum where the ends of the visible spectrum meet at violet.
You could be decades old when you discover that there isn't actually a purple crayon in the rainbow. The letter P doesn’t appear in ROYGBIV after all.
However, consider violet; surprisingly, it is not actually purple. Indeed, violet (like all other hues in a naturally appearing rainbow) possesses an attribute that purple lacks—it has its distinct color. wavelength of light Anyone who has experienced a sunburn understands that violet wavelengths truly exist since the Sun’s ultraviolet (UV) rays necessitate the use of sunscreen, despite these wavelengths being invisible to our eyes (we'll delve deeper into this topic shortly). The same goes for red, orange, yellow, green, blue, and indigo; they're equally genuine.
However, purple? It simply represents how your brain tries to resolve ambiguity.
Exactly. Red and blue (or violet) represent two opposing ends of the light spectrum. If your eyes detect both these wavelengths simultaneously, they become confused since they conflict with each other. As a result, your vision adjusts, causing those conflicting colors to be perceived as purple—an illusion that does not truly exist in nature.
The visible light spectrum Visible to the naked eye constitutes merely a tiny portion of all wavelengths (precisely 0.0035%). These hues are made available to us composed of millions of densely packed photoreceptor cells referred to as cones , which respond to light hitting our retina. We can only see colors that have wavelengths of the right sizes (between 350 to 750 nanometers) for our cones to respond to. That’s why we cannot make out UV or infrared light—UV wavelengths are too short for our cones to detect, and infrared wavelengths are too long.
Cone cells come in three flavors : short wavelength cones (S), medium wavelength cones (M), and long wavelength cones (L). Approximately 60% of cones are L cones that best absorb reddish wavelengths (as a result of the reddish pigments they contain), 30% are M cones that best absorb greenish wavelengths (and have greenish pigment), and 10% are S cones that best absorb bluish wavelengths (and have bluish pigment). All three types of cones can absorb many wavelengths near their maximum —even though this absorption weakens as you move away from the peak absorption wavelength—and they have overlapping capabilities in detecting colors such as yellow and teal.
Cones do not actually see Colors themselves do not directly interact with our perception; instead, they transmit electrical impulses according to the wavelengths they absorb via the optic nerve to a region in the brain known as the thalamus. Here, these signals undergo initial processing before being forwarded to the visual cortex. In this final stage, the visual cortex interprets how numerous cones have been stimulated by specific light wavelengths along with the intensity of these stimuli for each kind of cone. Subsequently, the brain assesses the disparities in signal power among various types of cones to ascertain the observed hue, thereby enabling an individual’s ability to discern approximately one million distinct shades.
When observing intermediate hues such as teal, your brain calculates the average response from different types of cone cells responsible for detecting those wavelengths. Teal light stimulates your S-cones quite intensely along with activating some of your M-cones. If there’s a higher intensity of blue compared to green, you interpret this blend as various shades of blue; conversely, an abundance of green over blue leads to perceiving it as distinct greens.
The issue with purple lies in the fact that it shouldn't technically be feasible to produce a hue using wavelengths found at opposing ends of the visible spectrum. Your S cones can detect violet light—the shortest observable wavelengths—while your L cones perceive red light—the longest observable wavelengths—but these do not intersect. As such, our brains close this gap by forming a circular loop within the visual spectrum, uniting both extremities through purple. This phenomenon represents a perceptual trick stemming from both physical optics and neural processing, leading us to believe we observe colors outside what should theoretically be achievable. nonspectral color .
Even though purple is essentially an illusion—a shade more akin to a product of our imagination—it has garnered a significant reputation as the hue of royalty, nobility, power, luxury, devotion, mystery, and magic. Perhaps the most fitting connection among these is the final one: magic.