These paintings use fluorescent paints to create a glowing effect when viewed under a blacklight. If you buy one of these paintings, we recommend you also get a blacklight (UV) bulb to go with it. These can be purchased in many places. I recommend the fluorescent type as opposed to LED type.
I’ve used both acrylic fluorescent and watercolour fluorescent paints, and I think both are fun to work with. Both types of paint shine well under ultraviolet light.