What is luminance?

Luminance is how bright something looks to your eyes, like how shiny a lemon is when it’s sitting on your kitchen counter.

Imagine you have two flashlights, one is small and weak, the other is big and strong. When you turn them both on, the big flashlight makes the floor look much brighter than the small flashlight does. That’s because it has more luminance, it sends out more light to your eyes.

Think of luminance like how much light is coming from something, just like when you put a lemon under the sun. The sunlight makes the lemon look super bright and yellow, almost like it’s glowing! But if you take that same lemon inside a dark room, it looks dull and not as exciting, because there's less light reaching your eyes.

So luminance is all about how much light something gives off or reflects, more light means brighter things, just like the big flashlight or a sunny lemon.