How to do light painting photography? Do you need post-production?

The color is relatively simple. You can find a colorful plastic shell or plastic bag and put the light source in it.

One of my daughter's toys, with many letters of various colors on it, is hollow. I put a flashlight in it to "draw", which is much brighter than the color you provided, haha. Color itself does not need much later, mainly depends on experience. When painting, the technique is better and you can play more.