There's a great youtube video called "Darker Than Vantablack" that has a cool demo of light reflecting off of different paints, etc; and at the end he revels how he got such a pure black without vantablack or a darker substance. It's neat! https://www.youtube.com/watch?v=JoLEIiza9Bc
The Action Lab! The first time I saw his channel I honestly didn't take the guy too seriously...but he is super creative and has some really cool ideas that most people could do at home if they wanted to.