Purkinje effect

Have you ever noticed that when the sun sets, everything looks a little blue? And when it's dark outside, things that are red look almost black? That is because of something called the Purkinje effect.

Inside your eyes, there are cells called rods and cones. They help you see colors and light. During the day, your cones help you see colors really well. But as it gets dark outside, your cones stop working so well, and your rods take over. Rods can't see colors very well, but they're really good at seeing light.

The Purkinje effect happens when you go from a well-lit area to a darker one. As the light fades, your cones stop working so well, and your rods take over. But they're not very good at seeing reds, so things that are red look darker to you than they really are. Blue and green things, on the other hand, look brighter and more colorful than they do in bright light. This is why the world can seem a little bluer at sunset or night time, and things that are red can seem almost black.

So, in a nutshell, the Purkinje effect is when your eyes adjust from bright light to dim light, and the colors you see change as a result.