Obtain glow-in-the-dark powder.
Glow powder comes in different grades ranging from Grade 0 on the high end to Grade 7 on the low end. The main difference between grades is brightness compared to cost. Within each grade, there are various particle sizes available ranging from 8 micron to 60,000 micron. Larger particles are brighter, but also make a rougher paint which can looked speckled.
If you are planning to use a water-based medium, then you will need "coated glow powder" also known as "coated phosphorescent pigment". For solvent or oil-based mediums, you can use standard or uncollated glow powder.
Obtain a paint medium
When choosing a paint medium, look for a paint that is clear, thick, and has no UV filters added. Solvent Based mediums have harmful fumes and are not safe for children and can catch fire. A water based medium is recommended for use indoors, or in children's rooms or with children's crafts. Consider buying a medium that is specifically designed to suspend phosphorescent pigment.
Add 20% by volume of glow powder to paint medium.
Stir and you're finished.
Depending on your powder/medium combination, your new mix may or may not have shelf life. Therefore only mix what you can use within an hour.
Finished.
http://www.wikihow.com/Make-Glow-in-the-Dark-Paint
