This style of tattooing, thought to have originated in the correctional system (prisons) came about in the 70’s. Black & Gray normally features a monochromatic (grayscale) palette using a single tattoo needle and black ink. Some of the most brilliant innovations in tattoo machines were surprisingly born of jailhouse ingenuity. Modern black & gray techniques are often employed to produce photo realistic imagery and especially portraits. These techniques generally result in a tattoo more resistant to ink deterioration and loss of detail.