eli5: Does the reflection of light in windows/mirrors also produce light?


Ever since I was young, I’ve always wondered if reflected light from windows also produces light. I never asked because I thought it was a “dumb” question. Guess this is the right place…

ps: sorry if I made mistakes, I’m not a native speaker 😉

In: 0

You answered your own question. A reflection doesn’t produce light, it reflects light. There is no energy production in a window for example.

It can still look like a light source though, just like the moon looks like a light source even though it’s just sunlight reflecting.

No. No additional light is produced. You’ll only ever see the light produced by the original source.

What you may think of as producing light (having it come through a window and you have bright spots on the ceiling) is light refracting. Meaning it bends the existing light.

No they reflect the available light, more reflective the material more it reflects.If light particles hit a mirror it will reflect most of it and absorb rest so if you reflect light trough couple of mirrors, eventually the last mirror will get completely dark.

Light hits an object…. All light is either reflected or absorbed..

If the object is rough it looks “lit” because when the rays reflect, they scatter in different directions (due to the “roughness” of the surface).
If an object is smooth the light reflects basically the way it came in… and you see an image (we typically call this a reflection).

Now most things have a “reflectance” – so just a portion of that light is reflected…. So you only see a “weaker” image reflected back.

When it comes to glass part of the light is reflected and the rest that isn’t reflected is refracted (passes through)

When it comes to a black object, it can still reflect (something black and shiny).. BUT the light that doesn’t reflect is absorbed by the black local color.

When it comes to something White, a same same but a lot more light is reflected by the local color (also called albedo)

All reflected light is a fraction of the initial light value from the source… the object can never be brighter than the source.

The lambertion shading model is crazy simple!

Source – I work in computer graphics.