Per Tennessee Dave, the great god-king of encyclopedic tattoo knowledge, the “tattoo font” and the word flash (sample posters of tattoo designs for customers to peruse) both come from the days when tattooists worked in the side shows of circuses and carnivals. The tattoo font is based on the font that appeared in side show signs and cards that advertised the services of tattooists.
Below is a sample tattoo font based on hand lettering done by Greg James.
For an actual font, that you can install on your computer, check these out:
The Tattoo Font at 1001Fonts.com – a dingbats style of font with little tribal tattoo symbols and FREE.
Tattoo Ink Font at dafont.com – the classic circus-inspired font in black and white and FREE.
Tattoo Lettering is an all black version with a hand-lettered look from GetFreeFonts.info and it’s FREE.