How Do We Actually See Color?

Summary

In this fascinating exploration of color vision, Joe dives into how the color of objects, like bananas, changes under different light sources. He explains that color is the result of light’s wavelength, but our eyes don’t perceive it the same way machines do. The video delves into the complexity of color vision, revealing how three types of cones in our eyes process light to create the sensation of color. With mind-bending experiments and a look into the science of color perception, Joe shows how our brain interprets colors and how it leads to phenomena like afterimages. Ultimately, he challenges viewers to reconsider how they see the world around them.

Takeaways

• 😀 Color perception is subjective and depends on various factors like lighting and the structure of our eyes.
• 😀 Bananas appear different colors under various light sources, such as red, green, and blue light.
• 😀 The human eye has three types of cones sensitive to different wavelengths of light: short, medium, and long.
• 😀 Our brains combine the signals from these cones to create a perception of color, but we don't see color the way machines do.
• 😀 The perception of color can be influenced by the overlapping sensitivity ranges of the cones.
• 😀 Colors like yellow can be seen even when combining different wavelengths of light, such as red and green.
• 😀 The color of objects is determined by the light they reflect, and our brain processes these reflected colors to interpret them.
• 😀 The human visual system perceives certain color combinations, such as blue and yellow or red and green, as opposites.
• 😀 Afterimages are a result of our visual system treating colors as opposites, with the brain flipping colors like red to green and yellow to blue.
• 😀 The way we see color is based on three channels: red vs. green, blue vs. yellow, and dark vs. light.
• 😀 The visual system allows us to perceive a million different hues with just three types of photoreceptor cells, even though our eyes are not like a camera.

Q & A

What color is a banana under different light conditions?

The color of a banana depends on the light under which it is viewed. Under red light, it looks red; under green light, it looks green; and under blue light, it appears black. Under a combination of red, green, and blue light, it appears yellow.

How does color vision work in the human eye?

Color vision in humans is facilitated by three types of cones in the retina that absorb different wavelengths of light—short, medium, and long. These cones work together to send signals to the brain, allowing us to perceive colors.

Why do we perceive the same color when red and green light combine?

When red and green light combine, the brain interprets the mixed signal as yellow, even though they are different wavelengths. This is because our visual system processes the combined input from the medium and long cones, which are sensitive to these colors.

What is the difference between how machines and humans perceive color?

Machines, like spectrometers, measure color by its wavelength, while humans perceive color through the complex interactions between different cones in the eye, which can lead to optical illusions, such as seeing two objects that are the same color as different.

How do cones in the eye differentiate colors?

The three types of cones in the retina are sensitive to different ranges of light wavelengths: short cones (blue), medium cones (green), and long cones (red). By comparing signals from these cones, our brain interprets and distinguishes various colors.

Why do some combinations of colors, like blue and yellow, not exist in the human visual system?

Colors like blue and yellow are considered opposites in our visual system. Our brains cannot perceive them simultaneously because the neural channels for processing colors are set up to detect one or the other but not both at the same time.

What are afterimages, and how do they relate to color vision?

Afterimages are visual phenomena that occur when a person stares at a colored image for an extended period, causing the brain to produce an opposite color after the image is removed. For example, staring at green will create a red afterimage. This is because the visual system treats some colors as opposites.

Why does a banana appear yellow under red and green light?

Bananas reflect both red and green light, which the human visual system processes as yellow, even though the individual lights are different. This is due to the way our cones interact and perceive combined wavelengths.

How do scientists measure color in a laboratory?

Scientists measure color using instruments that can detect the wavelength of light. By analyzing the wavelength, they can identify the inherent color of the light, which is a specific point on the electromagnetic spectrum.

What role does memory play in color perception under different lighting conditions?

Our brains use memories and prior experiences to adjust how we perceive color under different lighting conditions. This ability helps us recognize colors as constant (e.g., a yellow car remains yellow in both bright daylight and at sunset) despite changes in light quality.