A photopic curve is a graphical representation of the sensitivity of the human eye to light under well-lit conditions, such as during the day or in brightly lit environments.
- The photopic curve appears as a line graph that illustrates how sensitive the human eye is to different wavelengths (colours) of light in these bright conditions. This curve is essential for understanding colour perception and visual acuity in bright light. It shows the minimum amount of light required for the eye to detect various wavelengths.
- This information is derived from the response of our cone cells, which are responsible for colour vision and function optimally in bright light.
- Closely related to a photopic curve is a scotopic curve is a graphical representation of the sensitivity of the human eye to light under low-light conditions, such as at night or in very dimly lit environments.
- The scotopic curve also resembles a line graph that shows how sensitive the eye is to light in these low-light conditions. It is an important tool for understanding night vision. The curve illustrates the minimum amount of light needed for the eye to detect different wavelengths (colours) of light.
- This information comes from the response of our rod cells, which are more active in low light compared to the cone cells that dominate in bright conditions.
- It is interesting to note that the scotopic and photopic curves use different units to measure light. The scotopic curve uses units related to light intensity per unit area (such as brightness per square degree), whereas the photopic curve uses units similar to overall brightness.