Black and grey typically goes hand-in-hand with realism tattooing, however instead of using color, traditionally black and grey tattooing only uses black ink and water.  Tattooists will water down the black ink to make it softer and more grey in order to create shades, hues and color contrasts. Nowadays many newer artists will use grey washes, or pre-watered down black ink, as well as actual grey ink and white ink for highlights.