Okay kiddo, let me explain what luminance is. Have you ever turned on a lamp or a flashlight? The amount of light that comes out of it is what we call luminance.
Luminance is the brightness of something, like a light or a screen. When we talk about luminance, we are talking about how bright or dim something appears to our eyes. It's kind of like how loud or soft a sound is to our ears.
Luminance is measured in units called candelas per square meter, but that might sound a bit complicated for a five-year-old. Think of it like a score from 1 to 10, where 1 is very dim and 10 is very bright.
When we watch a movie or play a video game on a screen, we want the luminance to be just right so that it's not too bright or too dim. If it's too bright, it might hurt our eyes, and if it's too dim, we might not be able to see everything that's happening on the screen.
So, that's what luminance is, it's just a fancy word for how bright or dim something is. I hope that made sense, kiddo!