Prison tattooing is the practice of creating and displaying tattoos in a prison environment. Present-day American and Russian prisoners may convey gang membership, code, or hidden meanings for origin or criminal deeds. Lack of proper equipment and sterile environments lead to health risks such as infection or disease (hepatitis, AIDS) from contaminated needles.
There are many different symbols and numbers that represent multiple gangs or groups. Certain images like spider webs can represent the length of sentences. The well-known teardrop tattoo may mean one for each murder performed. Tattoos are also used to communicate who the inmates are as people - for example, white supremacists will display prominent tattoos to show their beliefs. Some common symbols used in this manner are the percentile 100%, a white supremacist indicator of racial purity; Valknuts; swastikas. Three dots arranged as a triangle, mean "mi vida loca" or "my crazy life" to Mexican inmates linked to the Mexican Mafia, while four dots have the same meaning but are found on Mexican gang members associated with the Nuestra Familia; a clock with no hands represents "doing time"; spider webs are a symbol of being trapped; or the number 13 to signify being unlucky.
Mostly seen in the UK but is used elsewhere too, a common prison tattoo is four dots tattooed across the knuckles of the criminal which stands for ACAB (All Coppers Are Bastards). Or a dot on each hand in between the thumb and forefinger, one meaning going into prison and one meaning they have completed their sentence.
In Ireland, a common tattoo ex-inmates give themselves is a simple dot placed under the right eye using Indian ink, colloquially known as a "jail dot".
A Borstal dot also meant doing time but this tattoo has become a lot less common since Borstals were abolished.
Another less common prison tattoo dates back to Borstals which earned itself the name the "Borstal glove" is the back of the criminal's hand outlined and just full of Indian ink.
Since the tattoo machines are homemade and efficient means of sterilization are not available, there are many health risks involved. Deadly diseases like hepatitis and HIV/AIDS can be passed from one person to the next through shared needles. Also, the makeshift ink can damage the skin, cause permanent scarring, or contain harmful chemicals.