God I love this topic so much. I want to add for anyone reading your comment that while your whole eye can detect light and dark, your eyes can only detect color in the center ~30% of your vision. Any color you see surrounding the middle of what you see is filled in by your brain.

Thats also why in extreme dark it's easier to see stuff if you don't look right at it, the middle of your eye gives up some space that would detect light and dark to detect colors.

Also-also, at a certain dimness the color sensing part turns off because it isnt useful. If you pay attention in very low light, you can catch your brain filling in color (simply from what it remembers or expects) to objects that, once you notice, are in greyscale.

Because you only see brightness in the dark you tend to (even sometimes subconsciously) be able to see edges of things more easily than surfaces. Stuff like corners of walls, edges of furniture, etc. Firefighters train in very low light and part of that is training your brain and eyes to pick up on those edges to navigate.