It has been established that with a brightness of more than 0.1 nits (the brightness of a white illuminated surface at full moon 0.07 nt, during the day in the room 3-100 nt) the decay of rhodopsin in rods is so intense that recovery always lags behind the decay and its concentration decreases sharply. As a result, the sticks become “blind”. In this case, almost exclusively cones are involved in the process of vision, and this condition is called daytime vision. However, cones are less sensitive than rods. At brightness levels of less than a few hundredths of a nit, the cones are virtually excluded from the vision process. In this case, only rods are involved in vision, and it is called night.
As already noted, sticks and various types cones have different spectral sensitivities. In this case, the total relative sensitivities of the three types of cones to homogeneous radiation determine the spectral sensitivity of the eye during daytime vision, which is shown in the figure below; more precisely, its standard version is shown - according to GOST 11093-64.
The relative sensitivities of the rods determine the spectral sensitivity of the eye during night vision. This curve is not shown in the figure - it is similar in shape, but its maximum is shifted to short wavelengths (~510 nm).
Rods are generally more sensitive to short-wave radiation than cones. Therefore, at dusk, blue objects appear lighter and red objects appear darker than in daylight. More Leonardo da Vinci(1452-1519, Italian painter, sculptor, architect, scientist, engineer, etc., etc.) noted that “green and blue increase their color in partial shade, and red and yellow gain color in their illuminated parts, and white does the same."
During the day, notice the contrast between the fiery scarlet geraniums in the lawn border and the background of dark green leaves. At dusk and late in the evening this contrast is completely opposite: the flowers now appear much darker than the leaves. You might be surprised to compare the brightness of red with the brightness of green, but the differences are so well expressed that there is no room for doubt.
If you find red and blue colors in an art gallery, which appear equally bright during the day, then at dusk you will find that the blue color becomes brighter to such an extent that the paint seems to glow.
Move away from city lights. At first the night will seem very dark to you; then, when your eyes get used to the darkness (the rods come into play), you begin to distinguish the surroundings. Look at heavily colored paper - it will seem colorless to you. A red sheet of paper will seem black to you, and blue and violet will seem gray-white. We are becoming color blind!
At the same time, thousands of stars with their silvery shine will appear in the sky. If you look at them closely, most of them will disappear, and only the brightest ones will remain, which will seem to us like small points of light. These observations are best carried out on dark nights and away from cities, but even under moonlight the landscape becomes for us, so to speak, a “stick landscape.”
All these are examples of the Purkinje effect ( Jan Evangelista Purkinje, 1787-1869, fundamental works on physiology, anatomy, histology and embryology, in 1839. founded the world's first physiological institute in Wroclaw, classical research in physiology visual perception, in 1825 discovered the nucleus of the egg), and is explained by the fact that rods give us the impression of light, not color.
But we digress, let's return to a more scientific presentation of the issue.
Speaking about the relative spectral sensitivity of the eye during daytime vision, we talked about the integral characteristics of the three groups of cones. Cones of each of the three groups have the greatest sensitivity in the long, medium and short wavelength zones of the spectrum; which is shown in the figure below.
When light acts predominantly on cones of one type, a sensation occurs a certain color; respectively, red, green and blue. Therefore, for brevity, groups of cones are called K3S-receivers, and the curves presented in the figure above are called curves of the main excitations.
The existence of three types of cones in the eye and the sensation of different colors when radiation affects different types of cones is the reason color vision. Since cones only work when high levels brightness - only daytime vision is color, and therefore - "at night all cats are gray"— remember the Purkinje effect.
To the question: What kind of effect is the Purkinje Effect? given by the author Embassy the best answer is Turn your face to the sun, close your eyes, and move your hand in front of your face. You will “see” flashing multi-colored balls.
When light acts predominantly on cones of one type, a sensation of a certain color arises; respectively, red, green and blue. Therefore, for brevity, groups of cones are called GSC receivers, and the curves presented in the figure above are called fundamental excitation curves.
The existence of three types of cones in the eye and the perception of different colors by the action of radiation on different types of cones is the cause of color vision. Since cones only work at high brightness levels - only daytime vision is color vision, and therefore - “all cats are gray at night” 
Purkinje noted in 1825 that the brightness of blue and red road signs in different times The day is different: during the day both colors are equally bright, and at sunset the blue seems brighter than the red. With the onset of deeper twilight, the colors completely fade and, in general, begin to be perceived in gray tones. Red is perceived as black, and blue as white. This phenomenon is associated with the transition from cone to rod vision as light levels decrease. 
Purkinje phenomenon - a shift in the maximum spectral photosensitivity of the observer when adapting to weak (twilight) lighting towards bluish-green tones (500 nm) from the maximum point day vision, lying at the wavelengths of yellow-green tones (555 nm). In twilight lighting, the colors of objects “cool”: red and yellow shades become dull, blues and greens become relatively brighter. 
We encounter manifestations of the Purkinje effect in everyday life, in everyday life, it has to be taken into account in a number of industries (for example, in the manufacture and use of dyes). Let us give an example of a phenomenon that is familiar to many from everyday life, but, apparently, not understood by everyone. On a clear sunny day in summer you see two flowers in a flowerbed: a red poppy and blue cornflower. Both flowers have rich colors, the poppy seems even more vibrant. Now remember what these flowers look like at dusk and at night. The poppy, like any red flowers, geraniums, salvias, carnations, appears black, and the cornflower has become light gray.
Here's another example. Look at a colorful rug during the day, which includes reds, oranges, greens, blues or blues, and then look at it at dusk or at night. In low light, all red and orange colors seem to “sink,” that is, they darken, and green and blue colors “bulge out,” becoming lighter. It seems that during the day it was a completely different carpet.
Embroiderers in the Ancient Greece: working under lamps, they often made mistakes in colors, mistaking one for another.
Astronomers have to take into account the influence of the Purkinje effect when photometrically (i.e., comparing the brightness) of stars of different colors.
The Purkinje effect can be experienced using Fig. 11 on the color tab. Find a room where the overall illumination can be reduced gradually. Look at fig. 11 Under normal lighting: the red bar will seem brighter to you than blue-green background. While you continue to look at the drawing, slowly reduce the light. You will see the colors gradually fade. Having reached low level light, you will see that the red stripe will become darker than the blue-green background surrounding it. It is possible that the red stripe will seem black to you and the background gray. It is at this point that your vision transitions from photopic (cones) to scotopic (rods).
Purkinje's discovery is based on his own observations over the objects around him. He noticed that the brightness of blue and red road signs is different at different times of the day: during the day both colors are equally bright, but at sunset the blue one seems brighter than the red one. What Purkinje observed was actually the result of a change in the perception of the brightness of light rays with different lengths waves caused by the transition from photopic to scotopic vision: in low light, in conditions when rod vision “works”, visual system becomes more sensitive to short-wave light than to long-wave light (see Fig. 4.4), as a result of which, in poor lighting, short-wave light appears brighter than long-wave light. Thus, due to the fact that at the onset of twilight photopic vision begins to “work”, we initially perceive long-wave “red” light as relatively brighter compared to short-wave “green” light, but as darkness sets in and the role of scotopic vision increases, initially reddish tones begin to appear darker gray than greens. When deep twilight sets in, reddish tones appear black. Since scotopic vision is colorless and all “colors” appear only as different shades of gray, as the light decreases, what was green in daylight becomes silver-gray, and what was red in daylight becomes silver-black.
Consequently, the English playwright John Heywood was right when he wrote in 1546: “When the candles are extinguished, all cats are gray.”
Red light and dark adaptation. The wavelength of light used to precondition the eyes of the person whose dark adaptation is being studied has certain practical implications. If light of a certain wavelength (650 nm or more, perceived as red) is used for this purpose, dark adaptation occurs more quickly after it is turned off than when light of a different wavelength is used. The reason is that, as photoreceptors, rods are relatively insensitive to long-wave light, as a result of which they have little effect on light adaptation.
An interesting idea is based on this observation. practical advice. If a person has to quickly transition from a well-lit room to a dark one, dark adaptation can be started in advance, while still in a lighted room, for which one needs to wear safety glasses with red lenses that transmit only long-wave light. As a preparation for night vision, pre-acclimation with long-wavelength (red) light is almost as effective as being in the dark.
Red safety glasses serve several functions. Like any similar filter, they reduce the amount of light entering the eyes, causing the eyes to adapt to less light. More importantly, however, red glasses only transmit long-wavelength red light, to which rods are particularly insensitive. Although cones are also relatively insensitive to long-wave red light, if the intensity of the latter is sufficient, they will still function at the same time that the even less sensitive rods undergo dark adaptation. In other words, red light only stimulates the cones. Consequently, when a person takes off his glasses in the dark, only the cones begin to adapt and dark adaptation occurs faster (see the upper curve of Fig. 4.1).
