How to do photographic light painting?

Find a room or environment as dark as possible, fix the camera with a tripod, low ISO, small aperture and long exposure. If it is a SLR, you can adjust it to door B and manually focus it to infinity.

The rest is mainly your creativity. If conditions permit, it can be exposed for many times, or created jointly by many people.

The original painting in the picture is also light painting, but the color is reversed in the later period.