Why Purple?
As you may already know, the color purple is the only color which
exists in our perception, and not as a single wavelength of light.
The rainbow of visible light from red to violet floods our
surroundings, but there is no such thing as purple light.
How does this work?
We perceive color thanks to three different types of color receptor cells, or cones, in our eyes. Each type of cone is sensitive to a range of colors, but one is most excited by red light, one by green and one blue.
So how do do see purple?
1. What we perceive as color is, of course, the response of
our visual system to different frequencies of light created by the
physical response of the cones sending electrical signals to the
brain.
2. Photons vibrating 450 trillion times a second bump into
a receptor in our eye and we experience red – a miracle in its own
right. Others vibrating around 575 trillion times a second arrive
and we experience green. Others vibrating at a frequency somewhere
between those two arrive and we experience yellow. These “yellow”
photons excite both the red and green cones, but we experience
this as yellow. So imagine instead that red and green light enter
our eyes simultaneously. Just as with yellow light both our red
and green cones get excited. So what’s the difference?
3. Well, in terms of our experience, there is none. We do
in fact “see” yellow. We might casually say that if you mix red
and green light you “get” yellow, but that’s not strictly true.
What you get is excited red and green cones and you perceive that
as yellow.
4. Okay, so what about purple? Well, if you mix red and
blue light you excite red and blue cones and you experience
purple. There’s no doubting that. But unlike yellow, if you look
for light whose frequency is halfway between red and blue to do
the same job you are slap bang in the middle of the greens, and
not surprisingly what you see is green, not purple at all.
5. So the only way we can experience purple is by seeing
red and blue simultaneously. **There is no such thing as purple
light.** No single frequency of electromagnetic radiation can give
you that purple feeling.
6. The experience of purple is an anomaly of the way we see
color and as such I would suggest that it is the most intimate and
personal of colors, created purely in the depths of our perceptual
system. This is not true of any other color but regal, sensual
purple.
7. Purple represents the necessity of two sides coming
together to form an experience that can only be perceived from
both parts.
8. Purple stands as a testament to the necessity of dual
components coming together to form an experience perceived from
both parts.
More cool purple history:
Be like rock:
