How Do We See?
What do we mean by colors?
When light (Sun Light) hits an object, the object reflects some of that light and absorbs the rest of it.
Some objects reflect more of a certain wavelength of light than others. That’s why you see a certain color.
For example, a lemon reflects mainly yellow light. A strawberry reflects mainly red light.
Objects that absorb all wavelengths of light appear black.
Objects that reflect all wavelengths of light appear white.
When light travels from one medium to another, the light is not reflected like it would be on a solid object. Instead, it bends. That’s because light travels at different speeds in different mediums. This is called refraction.
When light travels through a glass prism at an angle, the different wavelengths of light are slowed down by different degrees so that each color has a different angle of refraction. As a result, you can see all of the colors contained in white light.
How do we See?
A layer called the retina sits at the back of the human eye.
Retinas are home to two types of photoreceptor cells: rods and cones
These specialized cells convert light into signals that are sent to the brain, allows you to see.
We have 20 times more rods then cones
Cones are responsible for 100% of colors, rods are used to see in low lights
Process
Here’s how the entire process works.
Light hits an object.
Specific light waves reflect off some materials and get absorbed by others.
That reflected light enters the eye, where the lens focuses it toward cones and rods.
The cones and rods react to the light and encode it into signals that the brain can read.
These signals get sent to the brain through a complex network of neurons and synapses. The brain then perceives those signals as color.
Cones and Rods
There are three types of cones: red, green and blue. Each type respond to different wavelengths of light.
Long wavelengths stimulate red cones.
Short wavelengths stimulate blue cones.
Medium wavelengths stimulate green cones.
When different combinations of cones are activated, you see the world in color.
M-cones (Green Cones): Making up 32% of cones in the eye, M-cones, or green cones, respond to medium-wavelength, or green, light.
S-cones (Blue Cones): S-cones are also called blue cones since they pick up shorter wavelengths like blue. They only make up about 2-7% of total cones.
Rods: Rods work in low light and help us see at night with no color reception. They also play into our peripheral vision.
Color vision deficiency (CVD), often called color blindness, occurs when one type of cone is completely missing from the retina or simply doesn’t work
How does it work?
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