It is also known as Aquarell technique.
The name itself is also the definition: watercolor, or pigments mixed with with water. It was the first painting technique in the world, even cavemen used paints upon their cave walls that were either vegetable or mineral based which was was also diluted with water. At first look, it is very impressive, it seems quite simple and lightly. However, it is one of the most difficult painting style, since you can’t correct it. It gives a clean, transparent surface, the blends are visible (i.e. a wet in wet technique), and you can control them.
When it comes do working on a person’s skin, you have to design everything beforehand on paper, since when you are applying a tattoo, the pigment won’t work on the surface on the skin. Here, you have to insert the ink under the skin, and then you can create an effect that where the pigments blended accidentally.
These tattoos typically has broad brush strokes, it could also dripping or splashing paint. It mostly works when it’s done in color. It’s also exciting if you mix it with other techniques, either with linework or geometrical shapes – including water color can be an interesting addition.