In the real world, dimly lit scenes have characteristic washed-out colors. Objects that are bright red in daylight appear to be soft pink in moonlight. This desaturation is a result of the way that two types of light receptors in the human eye work: in bright lighting conditions, the color-sensitive cones provide the information the eye receives; in darker conditions, the achromatic rods take over, giving the eye much less color information, thereby making objects appear desaturated. The Night shader simulates this effect: it boosts dim lighting while keeping the colors desaturated, in way that is similar to how the human eye behaves.
When designing a night-time scene, it is essential that the Night shader is activated before the lighting is set. This shader has a significant effect on dim lights: what looks good before activating the Night shader will need to be adjusted after activating it.
Note that the Night shader simulates the way human eyes work in dim lighting, not the way a camera captures dimly lit images. Do not use this shader if the rendered image is intended to mimic a photographic look.
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