Over two centuries ago, physiologist Jan Evangelista Purkyne observed a fascinating phenomenon that has since been named the Purkinje effect. This effect explains why colors appear differently depending on the amount of light present. In low light conditions, bright reds may appear darker and almost black, while blues and greens tend to become more vibrant.
The upcoming total solar eclipse on April 8 will provide a unique opportunity to observe the Purkinje effect in action. As the moon gradually blocks the sun's face, the amount of available light diminishes, mimicking the transition from daylight to evening-level light. This rapid shift during an eclipse makes the contrast in color perception more noticeable.
During the eclipse, the eyes transition from using cone cells in bright light to rod cells in low light. This quick change causes red colors to appear muted compared to blues and greens. The cones and rods of the eyes work simultaneously during this adjustment period, known as mesopic vision, resulting in a gray or sepia tone look in the surroundings.
For those not in the path of totality, the Purkinje effect may still be visible during a partial eclipse where daylight dims. To observe this phenomenon safely, viewers should remove their eclipse glasses when looking at their surroundings, not directly at the sun.
To enhance the color contrast during the eclipse, viewers can wear red and green clothing. This will allow them to see the changes in color saturation more vividly. However, the Purkinje effect cannot be captured on cameras as it is a result of how human eyes interpret light.
Total solar eclipses are exciting due to their rarity and the various phenomena associated with them. The Purkinje effect adds another fascinating element to the list of reasons why eclipses are such captivating events.
