The human eye perceives colors because of the way light interacts with the retina, the light-sensitive tissue at the back of the eye. The retina contains two types of light-sensitive cells: rods and cones. Rods are more sensitive to light than cones, but they do not detect color. Cones are responsible for color vision. There are three types of cones, each of which is sensitive to a different range of wavelengths of light:

• Red cones are sensitive to long wavelengths of light (around 625 nanometers).
• Green cones are sensitive to medium wavelengths of light (around 535 nanometers).
• Blue cones are sensitive to short wavelengths of light (around 420 nanometers).

When light hits the retina, it activates the cones. The amount of each type of cone that is activated determines the color that we see. For example, if the red cones are more activated than the green and blue cones, we see the color red.

The human eye can perceive a wide range of colors because the cones can be activated to different degrees. This allows us to distinguish between many different shades of each color.

In addition to the cones, the retina also contains a small number of other cells that are involved in color vision. These cells help to sharpen the edges of objects and to improve our ability to see in low light.

The brain plays an important role in color perception. The signals from the retina are sent to the brain, where they are processed and interpreted. The brain also takes into account other factors, such as the lighting conditions, to determine the final color that we see.

So, the reason why the human eye perceives colors is because of the way light interacts with the retina and the way that the brain processes the signals from the retina.