Color Vision: The Science Behind How We See Color

Color vision shapes how we interact with the objects surrounding us. The main types of color vision are monochromacy, dichromacy, and anomalous trichromacy.

Color vision relies on photoreception and various cones in the human eye. The cones and rods interact with light to create color perception. Color vision is a crucial element in art, design, and marketing.

What Is Color Vision?

What Is Color Vision?

Color vision is the ability to perceive differences in the wavelengths of visible light. There are different cone cells in the eye’s retina. Each cone cell responds to a specific part of the visible light spectrum.

The combination of different light wavelengths helps the brain to perceive color. People with normal color vision can differentiate between subtle color variations. There’s less uniformity and the ability to distinguish between colors if you’re suffering from color blindness.

Accurate color perception helps discern the visual effects of an object or design. It’s also essential in fields such as art and brand recognition.

Types of Color Vision

The three types of color vision are monochromacy, dichromacy, and anomalous trichromacy. They refer to the number and types of photoreceptors (cones) responsible for color perception.


Individuals with one type of photoreceptor in their eyes have monochromacy. The absence of one of the three photoreceptors causes this rare type of color vision deficiency.

An individual with monochromacy views surrounding objects in black, white, and gray shades. Damage to light-sensitive cells in the retina and genetic mutation are leading factors.


Dichromacy is where one can distinguish two primary colors, green or red. It’s a type of color blindness that could be partial or complete, depending on a person’s genetics. People with partial dichromacy still differentiate between various shades of color. Those with complete dichromacy have no perception of any shade of color.

Anomalous trichromacy

An individual with anomalous trichromacy has all three photoreceptors, but one is abnormal. Color vision deficiency affects about 8% of men and 0.5% of women. Anomalous trichromacy is the most common deficiency. It involves the perception of red, blue, and green.

Lacking the sensitivity of these primary colors causes anomalous trichromacy. While the perception is a bit off, people with this condition still distinguish between different hues.

The Role of Photoreceptors in Color Vision

Photoreceptors play a crucial role in distinguishing various shades of a single color.

  • Distinguishing between hues, shades, and tones of color: The three types of photoreceptors are ganglion cells, cones, and rods. Each reacts to specific light wavelengths, making the brain distinguish between different shades of color. Rods, for instance, respond to light and dark. They allow the eye to distinguish between different levels of brightness.
  • Activating specialized neurons in the brain: Cones generate electrical signals and transmit them in the brain. These electrical signals process all the information about a color.
  • Color constancy processes: Entails perceiving an object’s color regardless of changes of light illuminating it. Color constancy interacts with different areas of the color system to compare information about a color.
  • Detecting light and transducing it into electrical signals: Photoreceptor cells detect light and transform it into nerve signals. Rods and cones in the retina absorb light, making the brain interpret the colors it sees.

The Color Perception Process

Color perception is the brain’s ability to process and interpret light wavelengths. It involves several stages.

Color Detection

Color detection occurs when light travels to the retina at the back of the eye. The photoreceptor cells (cones) detect the wavelengths of light. S-cones detect blue colors, M-cones detect green, and L-cones detect red hues. They also respond to their respective secondary colors.


The active cones send electrical signals to the brain for processing. For the brain to discriminate between colors, it uses past experiences and a person’s color vision ability. Individuals with color deficiencies find it challenging to distinguish between specific colors. But trichromats can detect a wide range of colors and differentiate between them.


Color appearance refers to how we perceive an object’s color. The appearance of color depends on the viewing angle, light source, and background. In some viewing conditions, metamerism occurs, and different colors appear the same.