A spectral color is a color that is evoked in a normal human eye by a single wavelength of light in the visible spectrum, or by a relatively narrow band of wavelengths, also known as monochromatic light. Every wavelength of visible light is perceived as a spectral color, in a continuous spectrum; the colors of sufficiently close wavelengths are indistinguishable for the human eye.
The Visibility of Color
There are colors that cannot be perceived by the normal human eye. Our human eye can only see colors that fall within our visible color spectrum. Outside the color spectrum, we have ultraviolet and infrared light. Keep in mind that objects reflect colors they absorb.
The spectrum contains a division of colors based on their wavelengths as violet is assumed to be shorter and red to have a longer wavelength in the color spectrum. The range of the human color spectrum is about 400 nanometers in wavelength to 700 nanometers in wavelength. This means that any color that has a wavelength within this range should be seen by the normal human eye.
The spectrum is often divided into named colors, though any division is somewhat arbitrary; the spectrum is continuous. Traditional colors in English include red, orange, yellow, green, blue, and violet. In some other languages, the color names’ ranges do not necessarily agree with those in English.
The color spectrum is a collection of the colors that are displayed when light passes through a prism with each of them ordered by emission or wave.
What colors are visible in our spectrum?
- Red has a wavelength interval of 700–635 nm and a frequency of 430–480 THz
- Orange has a wavelength interval of 635–590 nm and a frequency of 480–510 THz
- Yellow has a wavelength interval of 590–560 nm and a frequency of 510–540 THz
- Green has a wavelength interval of 560–520 nm and a frequency of 540–580 THz
- Cyan has a wavelength interval of 520–490 nm and a frequency of 580–610 THz
- Blue has a wavelength interval of 490–450 nm and a frequency of 610–670 THz
- Violet has a wavelength interval of 450–400 nm and a frequency of 670–750 THz
So what about colors that have wavelengths shorter than 400 nanometers or longer than 700 nanometers?
In elementary school when we first started learning about colors, we were taught that there are three primary colors. Which meant that other colors we see are a combination of some of the three. We, humans, are typically trichromats, which is why we refer to people who can only see two colors as color blind. But some species of shrimp, like the mantissa, will view us as color blind seeing as they have longer color spectrum than we do and therefore can see more colors outside of our color spectrum.
How We Perceive Color
Many people, however, have argued that color is a concept of perception. And without perception, there are no colors. So if we can’t see it, then it is not there. However, this triggers the question of how color blind individuals fit into this. They cannot identify or differentiate particular colors; does it mean those colors do not exist? No!
So if we had the capability to expand our color spectrum (probably wishful thinking) or somehow see out outside of our restricted color spectrum by some enhanced technology, then everything would be different.
If our eyes could perceive deeper into the infrared light then each object will appear more colorful based on their heat signature. The world would explode into a version of wonderful colors but there is no telling how these colors will appear to us. Maybe we will be able to see brand new colors that our imagination now lacks comprehension and description or maybe we will still see the same colors but with deeper wavelengths.