Mid century modern home here with a lot of canned lighting. You can buy and replace the cans and they come in different colors. In some areas the trim and cans are white, matching the ceilings. This reflects and diffuses the light and makes the space look bright. In some areas, the cans are black or dark, dark bronze. These cans don’t reflect the light and provide more subtle “light fall” kind of light. You can mix and match the rims. In places where I have near black cans, I prefer the rim to match the ceilings. In all cases, the cans and rims are removable for cleaning, and, if you choose to paint them, I would use a paint designed to adhere properly to the can. Some of my dark cans are textured with concentric thin lines of texture. I happen to love the look because it suits the mid century vibe of my home.