The Science of Color Vision

The Science Behind Color Vision

Our eyes see color by detecting light and translating it into signals the brain understands.

• Light travels through the cornea, pupil, and lens, and is focused on the retina at the back of the eye.
• The retina contains two types of light-sensitive cells:     rods (for low light) and cones (for color and detail).
• There are three types of cones in the human eye, each sensitive to different wavelengths: S-cones (blue, short wavelengths), M-cones (green, medium wavelengths), and L-cones (red, long wavelengths).
• Cones detect specific wavelengths of light and convert them into electrical signals, which are sent to the brain through specialized retinal ganglion cells.

How the Brain Understands Color

The brain plays a big role in helping us experience the colorful world around us.

• The optic nerve carries signals from the retina to the brain’s visual cortex, where they are processed into images.
• The brain processes the cone signals and interprets combinations to produce a wide spectrum of colors.
• Color perception is affected by context, lighting conditions, and surroundings—this is why colors may appear different in various environments.
• In color blindness, one or more cone types are missing or malfunctioning. The most common type is red-green color blindness.

Fun Facts

Here are some interesting facts about color vision:

• Your eyes can distinguish about 1 million different colors.
• Some rare individuals possess a fourth cone type, enabling them to perceive more colors — a trait known as tetrachromacy.
• Some animals, such as the mantis shrimp, have many more cone types than humans and can perceive colors that we cannot even imagine.
• Dogs have only two types of cones (blue and yellow), so they mainly see shades of blue, yellow, and gray.

Review

Let’s quickly recap what we learned about color vision:

• What part of the eye detects color? Cones
• What carries the signals from the eye to the brain? Optic Nerve
• Where are cones located? Retina
• What is the part of the brain that processes vision? Visual Cortex