I'm pretty sure it's best to apply makeup in a well-lit room. While looking in a mirror.
Not a dark closet with no chance of viewing your reflection.
Maybe that's just me though.
Apparently my 4 year old has another opinion. It's a good thing her makeup is only an empty case with dried nail polish inside to look realistic. Otherwise, we might have a clown in our midst.
Although, that might help keep the boys away when she older. Hmm . . .