Quick Answer
No, people do not see colors in total darkness. The human eye requires at least a small amount of light to be able to see color. In complete darkness, there is not enough light entering the eye for the color-sensing cones in the retina to function. However, some colors may appear more visible in low light conditions because of how our eyes adapt to the dark.
What is required for humans to see color?
For humans to see color, light is required. When light enters the eye, it hits the retina containing photoreceptor cells. There are two main types of photoreceptors: rods and cones.
Rods are sensitive to brightness and motion, but do not detect color. They work well in low light conditions. Cones are specialized to detect different wavelengths of light corresponding to different colors. There are three types of cones, each responsive to red, green or blue light.
Color vision requires all three types of cones to be stimulated by light. The brain combines the signals from the different cones to perceive a full range of colors. Without sufficient light levels, the cones are not activated and no color is seen.
How does vision change in low light and darkness?
In dim conditions, our vision shifts from being cone-dominated to rod-dominated. The rods take over, allowing us to see shapes and movement, but color vision diminishes.
As light levels drop, the first colors we lose the ability to see are the shorter wavelengths of blue and green, which require more light to stimulate the cone cells. Reds and yellows remain visible longer since the red and green cones have some overlapping sensitivity.
But in total darkness, where no light enters the eye, both the rods and cones stop functioning. We lose all vision, seeing only blackness with no light, shapes, motion or colors detectable.
Do some colors appear brighter in low light?
Although we cannot truly see color in the dark, some wavelengths and hues appear brighter to us as light dims. Shorter wavelength colors on the blue end of the spectrum fade first. Longer wavelength warm colors like red, orange and yellow appear brighter at night.
This is why red lights are used on the back of vehicles – red is highly visible and bright to our night vision compared to other colors. Using blue or green lights at night would make objects harder to see.
The boost in brightness of warm colors is due to a phenomenon called the Purkinje effect. It describes how the eye’s color receptors or cones change sensitivity in low illumination. The rods take over, but the red cones remain more active than the green and blue cones. This makes reddish colors look relatively enhanced or vivid in low light.
Do other animals see color in the dark?
Some animals have better night vision and ability to discriminate colors in low light compared to humans. These include:
| Animal | Features aiding night vision |
|---|---|
| Cats | More rods for night vision. Cones have sensitivity shifted to blue-green light. |
| Rats | High ratio of rods to cones. Rods are sensitive to ultraviolet light. |
| Owls | Tubular-shaped eyes to focus light. Increased density of rods and cones. |
| Moles | Only have blue cones, allowing color vision underground. |
These specializations allow many animals to see better than humans in night and low light environments. But even animals cannot see color in complete darkness when no light is available. Some enhancements like more rods or light-focusing eyes help maximize use of very low ambient light. But the limits of color vision still apply when light levels drop below the threshold of cone cell stimulation.
Can color be perceived in dreams or imagination?
Although we do not see actual colors in total darkness while awake, there are reports of perceiving color in dreams, hallucinations or mental imagery while the eyes are closed.
These experiences arise from brain activity alone, without external light entering the eye to stimulate the cones. During dreams or imagined perceptions, the visual cortex is thought to recreate colors and images by exciting neurons in patterns similar to seeing real objects and colors with open eyes.
However, the subjective experience of color in dreams varies between individuals. Some report dreaming only in black and white. Others describe dreams with muted or washed out colors. Vivid lifelike color in dreams is less common. This may reflect differences in how our brains reconstruct the experience of color internally when not stimulated by real light from the outside world.
Can colors be induced with neural stimulation?
Research has shown that artificial stimulation of the visual centers of the brain can produce the sensation of seeing light and color, even in blind subjects.
In one experiment, researchers placed electrodes inside the brains of blind patients and delivered mild electrical currents. This made patients report seeing spots of light or color, including yellow, green, red, blue and orange. The results showed that neural circuits in the visual cortex are still capable of producing color sensations, even when the eye and retina cannot detect light due to blindness.
However, the colors induced were relatively basic blobs and patterns. More sophisticated electrical stimulation would likely be required to reproduce complete images or scenery with vivid colors. But this demonstrates that our brain has an inherent ability to generate a range of color sensations outside of external visual inputs.
Conclusion
In summary, humans and animals require at least low levels of ambient light to stimulate color vision through the eye. In complete darkness, no colors can be perceived through our eyes due to the lack of cone cell activation. However, some colors like reds and yellows may appear brighter at night because the eye partially shifts to rod vision. With the help of neural processing, colors can also be reconstructed internally during dreams or hallucinations, or induced through direct brain stimulation in blind patients. But real external light is needed for full, vivid color perception through the eyes in waking life.
