The books have established that the invisibility cloak that Harry owned was the real deal (one of the Hallows) and not something you can buy in a shop. From this link we know that even though invisibility Cloak is immune to some forms of magic like Accio and probes which detect dark magic, it wasn't in general immune to curses and hexes. I want to know what would happen if someone, fully concealed by the invisibility Cloak was to cast a lumos spell? The light would obviously not be able to penetrate outside of the Cloak? So, would that work somehow like "hand of glory" and show light to only the person concealed in the Cloak? Or would it not light anything at all?

The books have established that the Invisibility cloak that Harry owned was the real deal (one of the Hallows) and not something you can buy in a shop. From this link we know that even though the Invisibility Cloak is immune to some forms of magic like Accio and probes which detect dark magic, it wasn't in general immune to curses and hexes. I want to know what would happen if someone, fully concealed by the Invisibility Cloak was to cast a Lumos spell? The light would obviously not be able to penetrate outside of the Cloak? So, would that work somehow like the "Hand of Glory" and show light to only the person concealed in the Cloak? Or would it not light anything at all?