You might, or might not be aware of my passion for black clothing. I like the simplicity and absence of noise.
Anyway. You might not be aware of the wonderful world of black as-in paint.
Apparently the current record holder in blackness (measured in percent absorption of visible light) is a product called “Vanta Black”.
Vantablack is a material developed by Surrey NanoSystems in the United Kingdom and is one of the darkest substances known, absorbing up to 99.96% of visible light (at 663 nm if the light is perpendicular to the material).Wikipedia: Vantablack
The name is a compound of the acronym VANTA (vertically aligned carbon nanotube arrays) and the color black.
Unfortunately this blackest-of-black coating is not readily available for purchase. Export rules apply and so it’s usually not sold to civilians at all.
“What is the next best thing?”, you ask. Well it’s BLACK 2.0.