Commercial photog here and one of the toughest assignments was first year shooting ‘black on black’. A small shoe sized box that was painted or gaff taped fully black then in studio shot at 3/4 angle to camera with some ‘down angle’ to see the top and using only one light. (one test was one light and using mirrors for bounce etc and another was using only a flashlight with a long exposure while painting the light)

The goal was to not have any side ‘merge’ with the black surrounding areas and light the edges in just enough fashion to showcase the shape without merge all the way around the box… absolute challenge and one that a few class mates and I still laugh at how hard it was but also showed just how much understanding light and how to use/manipulate it matters… this pertains to commercial product photography prob the most but the lesson apply to any object of any size. How can you show its dimension without allowing any one side to merge into the same tonal range and flatten the image.

For landscape the well lit foreground that separates from the middle ground and the background also does not merge with the other elements…. And on and on…

I will never not forget the critique of that assignment where any tiny amount of merge was pointed out.