The Purkinje effect or the Purkinje phenomenon (after Jan Evangelista Purkinje ) is the term used to describe the different perception of brightness for colors during day and night. It is based on the different spectral sensitivity of the visual cells ( photoreceptors ) during day and night vision, as shown in the V (λ) or V '(λ) curve . The cones are particularly active during the day and the chopsticks in particular at night .
Since the rods react particularly strongly to blue-green light with a wavelength of approx. 500 nm, the sensitivity of the human retina shifts in this direction in the dark . This is illustrated by the example of a geranium (picture below right): in bright sunlight the flower appears in a bright red next to the weaker green of the leaves and the blue of the neighboring flowers, while the contrast is reversed in darker light, and the blue and green tones appear comparatively light next to the dull red of the geranium leaves. Because of this effect one used z. B. in older submarines red light for interior lighting if night observations were planned. Because with red light, the rods are little stressed and the eye is better adapted to see in the dark ( dark adaptation ). This made it possible to look through the periscope of the submarine at night without having to adjust the eyes for long to the darkness outside the boat.
- www.biokurs.de: Adaptation, light sensitivity, pupillary reflex, visual pathway, afterimages (Internet Archive, last March 9, 2020)