Bathroom?

Hi Beverly, have you replaced the lighting you do have with LED bulbs? That would be one step toward a lighter bathroom. If the walls are painted dark, perhaps a new lighter paint would improve the darkness. Also adding light colored soft goods will help the room feel more light.

We have a bathroom with no window. For years it was painted a dark red, now it is white, however the paint didn't make a difference. It was always bright due to three high hat pot lights (in small area) with LED bulbs and a fan light over the shower. Plus I have large mirrors on both walls to reflect the light. Hope that helps!

Paint a light and bright color

Hi Beverly besides new lighting and a brighter color on the walls you could consider brighter accessories as well. Also, we have a bathroom with no window and I tried to embrace the idea of it being "cozy" and that helped me change up my thinking about it being "dark" lol

Paint a bright and light color like SW sea salt. Change linens to bright colors. Change out your bulbs to the new brighter ones. Add fixture if you can.

17 Homemade Fake Window Plans You Can DIY Easily

https://www.wcmanet.org/how-to-make-fake-window/

If your light fixtures are old and have plastic covers, replace them with new covers, new fixtures, and of course, as others above have noted, with LED bulbs, or integrated LED fixtures. Over time, plastic light covers tend to take on a yellowy discolouration which blocks light from being emitted from the bulbs.

When choosing LED light bulbs, keep in mind that the type of LED light can change the perceived paint color on the walls. For this reason I would suggest to change the lighting in the bathroom first before repainting.

Warm LED light casts a more yellowy shade and is not as bright as the cool LED light, which is brighter and whiter. Here are some examples to show how the different kinds of LED light vary according to their Kelvin rating:

Contrary to popular belief, painting light colors in dark rooms does not brighten them up, they make them look dingy and dull. Opt for new bulbs, fixtures or increase the variety of light fixtures like lamps, add more reflective surfaces, fun patterns, and lively decor.

Depends on your budget, but we put in a skylight.

https://www.mirashowers.co.uk/blog/how-to/how-to-brighten-up-a-bathroom-with-no-windows/ here's some really great tips which can be very helpful.

We put a solar tube in our spare bathroom since the only window is tiny. Cost under $100 at Lowes and the bathroom is now flooded with natural light.