Green Light

You may notice the lack of my usual  visual for this particular post to the blog.  It is rather poetic. Read and find out why.

Light is electromagnetic radiation. In the back of the eye, there are sensors called rods and cones.  Collectively, they sense light or the absence of light.  The cones distinguish the colour of the light, from the visual spectrum (between 700 and 400nm).  There is a cone for Red light, blue light, and green light.

The colours of items are determined by their pigment. Molecules absorb certain wavelengths of radiation, and reflect others.  The wavelengths that get reflected are what our eyes perceive as the colour of that object.

But no object can reflect light without a light source.  It must come from somewhere.  Most sources of light tend to emit the whole spectrum of visual light.  This is called white light. But some light sources emit only a specific colour or wavelength of light. 

When looking at a light source, the intensity of sensation on the light receptors in the eye increases. Muscles in the eye, called the iris, will cause the pupil (the hole through which light enters the eye) will close, so less light can enter.  Extended exposure to such a stimulus will cause pain.

And so, I attempt to describe my personal experience.  Which may or may not be the same as anyone else’s, but that is psychology, a discussion for another time.

First, I see.  To see is to perceive light with the eyes.  I am looking. To look, is to direct my eyes. I cannot control what I see, only that which I look at.  I perceive a light source. It is bright, intense. It hurts my eyes after several moments. It is green.  The wavelength of the electromagnetic radiation is approximately 510 nm.  There are designated cones to sense this colour, and it feels like they are working overtime.  

Green is between blue and yellow in the spectrum; colored like grass or emeralds. Saying that would have been how most people would describe it, or just naming other things that match such a description.

But how do you describe such a sensation to a blind man?

You can say what a thing is, what it does, even how it does it.  I am sorry, but I cannot give you understanding, because you cannot see.   But figuratively, to look at is to focus on, or to concentrate thoughts upon.

Remember, you can’t control what you see. The world is as it is.  But you can control what you look at.