Under the dim light, we are able to see the objects but cannot distinguish between their colors why?
We can define color as a visual effect i.e. actually caused by the spectral composition of light which can be emitted, transmitted, or reflected by an object.
When light hits an object then the object absorbs some of the light and reflects back the rest. Our eyes and brain work mutually and change light into its constituent colors. Next, the photoreceptor cells of eyes transmit these signals to the brain which in return produces a sensational effect of color.
Our eyes have two types of photoreceptor cells or colour sensing cells in retina know as – Rod Cell, Cone Cell
- Rod Cell: These are types of photoreceptor cells that are concentrated at the peripheral portion of the retina. It is cylindrical in shape and contains a pigment Rhodopsin also know as Visual purple, which functions only under dim light. These cells are associated with Scotopic vision i.e. vision under low light intensity.
- Cone Cell: These are types of photoreceptor cells that are concentrated at the yellow central spot (i.e. Fovea). These cells are wider in shape and contain three different types of photopigments know as
- Lodopsin (also know as Visual violet which functions only in daylight).
These cells are associated with photopic vision i.e. high light vision.
Now it is understood from the above extracts that under low light intensity only Rod Cells of the retina are active which helps us to see the object but cannot distinguish between its colors.