The chances are as a photographer that you pay close attention to light and colour, even if you don’t have a camera in your hand. It’s possible then that you might have noticed how your colour perception changes as the light fades.
It’s self-evident that we have no colour vision in the dark. You only have to wake up in the night, give your eyes a moment to adjust, and see for yourself.
But have you noticed how anything that’s red, or perhaps yellow or orange, tends to appear more dull as the light fades while anything that’s blue looks more vivid?
That’s because human vision is dependent on rod and cones cells within the retina. Cones are responsible for photopic vision, making them active in well-lit conditions. Rods, on the other hand, are responsible for scotopic vision, or when it’s dark. Cone cells are capable of detecting colour, whereas rods are essentially colour blind but more sensitive to light at the bluer end of the spectrum.
In failing light we will be able to detect blues and greens above reds and yellows, with the former appearing brighter and the latter more dull. The prevalence of blue-grey tones can give everything a subtle, slightly mystical appearance.
This period of visual transition is know as the Purkinje Shift. (Or Purkinje Effect, both are acceptable terms.)
And if you did happen to be taking photos while your eyes are adapting to the fading light, you might well notice that the subtle blues and misty greys that you saw aren’t rendered entirely accurately by your camera. Your images might look a little more yellow. Maybe even more garish.
Your eyes or memory have not failed you and your camera is still working.
It is of course because your camera doesn’t have rods and cones. It simply detects light, wherever on the spectrum it falls. Where we might be seeing reds as dull and blues as more pronounced, the camera is detecting them as it always does. Our photos won’t necessarily resemble what we saw.