Absolute nothingness is, by definition, colorless and transparent. In an area of nothingness, there is the absence of anything to emit any light (or anything else) and the absence of anything that changes the color of any light (or anything else) passing through it. In short, absolute nothingness would look like, well, nothing. Moreover, if you had an area of absolute nothingness on your world, it would immediately cease to exist because the atmosphere and light entering it makes it no longer absolute nothingness.

Now, let's say that your volume of absolute nothingness instead instantaneously deletes light, matter, and anything else that enters it. Then it would be the most perfect black possible, since no light can be emitted from such a region or pass through such a region and there is nothing within it to reflect light. If you want to see what this might look like, look up pictures of https://en.wikipedia.org/wiki/Vantablack ; the visual effect is very startling. (As an aside, such a destructive void would also be rather problematic, since air would constantly be rushing into it and being deleted, not unlike a large vacuum cleaner. This would eventually consume the entire atmosphere of the planet, rendering it lifeless.)

If you want a more fantastical take on it, you might consider using Larry Niven's take on hyperspace: The human mind utterly couldn't comprehend it so a person looking out a window in a ship in hyperspace would perceive everything around the window but not the window itself. One of the characters places himself in a situation where his entire field of vision is hyperspace and his mind simply locks up until another character jolts him out of it.

Absolute nothingness is, by definition, colorless and transparent. In an area of nothingness, there is the absence of anything to emit any light (or anything else) and the absence of anything that changes the color of any light (or anything else) passing through it. In short, absolute nothingness would look like, well, nothing. Moreover, if you had a volume of absolute nothingness on your world, it would immediately cease to exist because the atmosphere and light entering it makes it no longer absolute nothingness.

Now, let's say that your volume of absolute nothingness instead instantaneously erases the existence of light, matter, and anything else that enters it. Then it would be the most perfect black possible, since no light can be emitted from such a region or pass through such a region and there is nothing within it to reflect light. If you want to see what this might look like, look up pictures of https://en.wikipedia.org/wiki/Vantablack ; the visual effect is very startling. (As an aside, such a destructive void would also be rather problematic, since air would constantly be rushing into it and being deleted, not unlike a large vacuum cleaner. This would eventually consume the entire atmosphere of the planet, rendering it lifeless.)

If you want a more fantastical take on it, you might consider cribbing Larry Niven's description of hyperspace, as best I recall it: The human mind utterly couldn't comprehend it so a person looking out a window in a ship in hyperspace would perceive everything around the window but not the window itself; it was as if where one side of the window frame ended, the opposite side immediately began. One of the characters places himself in a situation where his entire field of vision is hyperspace and his mind simply locks up until another character jolts him out of it.

Absolute nothingness is, by definition, colorless and transparent. In an area of nothingness, there is the absence of anything to emit any light (or anything else) and the absence of anything that changes the color of any light (or anything else) passing through it. In short, absolute nothingness would look like, well, nothing. Moreover, if you had an area of absolute nothingness on your world, it would immediately cease to exist because the atmosphere and light entering it makes it no longer absolute nothingness.

Now, let's say that your volume of absolute nothingness instead instantaneously deletes light, matter, and anything else that enters it. Then it would be the most perfect black possible, since no light can be emitted from such a region or pass through such a region and there is nothing within it to reflect light.  (It would also be rather problematic, since air would constantly be rushing into it and being deleted, turning it into a large vacuum cleaner and eventually consuming the entire atmosphere of the planet, rendering it lifeless.)

If you want a more fantastical take on it, you might consider using Larry Niven's take on hyperspace: The human mind utterly couldn't comprehend it so a person looking out a window in a ship in hyperspace would perceive everything around the window but not the window itself. One of the characters places himself in a situation where his entire field of vision is hyperspace and his mind simply locks up until another character jolts him out of it.

Absolute nothingness is, by definition, colorless and transparent. In an area of nothingness, there is the absence of anything to emit any light (or anything else) and the absence of anything that changes the color of any light (or anything else) passing through it. In short, absolute nothingness would look like, well, nothing. Moreover, if you had an area of absolute nothingness on your world, it would immediately cease to exist because the atmosphere and light entering it makes it no longer absolute nothingness.

Now, let's say that your volume of absolute nothingness instead instantaneously deletes light, matter, and anything else that enters it. Then it would be the most perfect black possible, since no light can be emitted from such a region or pass through such a region and there is nothing within it to reflect light. If you want to see what this might look like, look up pictures of https://en.wikipedia.org/wiki/Vantablack ; the visual effect is very startling. (As an aside, such a destructive void would also be rather problematic, since air would constantly be rushing into it and being deleted, not unlike a large vacuum cleaner. This would eventually consume the entire atmosphere of the planet, rendering it lifeless.)

If you want a more fantastical take on it, you might consider using Larry Niven's take on hyperspace: The human mind utterly couldn't comprehend it so a person looking out a window in a ship in hyperspace would perceive everything around the window but not the window itself. One of the characters places himself in a situation where his entire field of vision is hyperspace and his mind simply locks up until another character jolts him out of it.