As well as normal tattoos, there are a number of options available for getting tattoos that glow in the dark.
Temporary Glow in the Dark Tattoos
These are tattoos that only last for a short time, and can always be removed. They are applied to the skin's surface.
Glow in the dark transfer tattoos are temporary stickers that have had phosphors added to them so that they will glow in the dark. Otherwise, they are identical to normal temporary tattoo stickers. These will normally come on a sheet with a number of different, but usually related, tattoo designs. They will fade and come off naturally over time, although they can be removed earlier if desired.
As with normal temporary ink tattoos, which are applied onto the surface of the skin, you can also get inks that can be applied in a similar manner, both phosphorescent and fluorescent, that can be applied in a similar manner. These will also wear off and fade in time.
Permanent Glow in the Dark Tattoos
As well as temporary glow in the dark tattoos, you can also get permanent ones. The only difference these have compared to a normal tattoo is the inks used.
Glow in the Dark Tattoo Ink
This is just a tattoo that has been done in glow in the dark ink. This works by phosphorescence; absorbing light then emitting it back out later.
Whilst normal glow in the dark tattoo ink works by phosphorescence, absorbing light then re-emitting it later, blacklight inks work using fluorescence. These inks will only glow when exposed to non-visible UV light (such as under a blacklight), and will cease to glow once the light source has been removed.
Don't Get Permanent
At least to start with, don't even think about getting a permanent tattoo applied with glow in the dark ink. Tattoo removal is both more expensive and more painful then getting the tattoo. Sure, it may look cool at least initially but, unless removed, tattoos are for life, not just for a few days. Remember that if you want to sleep in the dark, that tattoo is going to glow as soon as the lights are off and, if you have a partner, it's not just you that will have to live with it.
It is by no means certain that either glow in the dark or blacklight inks are safe to use in tattoos, and the long term effects are still largely unknown. It is highly recommended that you seek professional, medical advice before having a tattoo of this nature done.
Should I Get One?
Temporary glow in the dark tattoos can be a fun novelty. Permanent ones are not recommended due to potential health issues and their long term nature unless expensive and painful removal treatment is undertaken.