To understand how this works we need to think about how we see. We see objects because light is being reflected off of the object and into our eyes. Most of the light we encounter is white light, white light is made of all the colours of the rainbow or in a more technical term, the visible spectrum. The way we see colour is that coloured objects absorb some colours of light and reflect others, for example, a red object is reflecting red light and absorbing the rest, so we see it as red.

The colour black absorbs most of the light which shines onto it which is why it appears to be so dark. The inside of the drum is actually in darkness as there is very little light getting inside of the small hole in the lid, let alone escaping back out of the small hole and being reflected into your eyes. When you open the lid the light floods in and is reflected into your eyes.

Vantablack is the darkest known substance as it always almost no light to escape its surface (only about 0.035% of light is reflected), it was developed by Surrey Nanosystems. It achieves its darkness due to its structure which comprises of an enormous amount of carbon nanotubes, to give a sense of scale, if you had one centimetre squared of Vantablack it would contain a billion nanotubes which are about ten thousand times thinner than a human hair (about one atom wide). Vantablack therefore is not really a colour at all as it does not involve any pigmentation, but rather it’s the absence of colour.