Why do you see black spots after looking into bright light?

When you look at a really bright light, like the sun or a camera flash, it can make your vision temporarily change. After you look away, you might see dark spots or patches in your vision, which are called afterimages. 

Afterimages happen because the cells in your eyes that help you see, called photoreceptor cells, get tired from the bright light. There are two types of these cells: cones and rods. Cones help you see colors and details, while rods are more sensitive to dim light. 

When you stare at a bright light, the cones in your eyes get worn out and don't work as well for a short time. Then, when you look at something else, the rods become more active than the cones. Rods are better at seeing in dim light, but they're not as good at seeing colors. That's why you might see a dark spot or patch that looks like a negative image.

Afterimages usually last a few seconds to a few minutes before going away. During this time, your eye cells need a break to recover and start working normally again.

Remember, it's important to avoid looking directly at bright lights, especially the sun, because it can harm your eyes. Bright lights can damage the cells in your eyes, which could cause vision problems. So, it's best to protect your eyes and not stare at bright lights.