What material should be included in a tattoo artist portfolio?

An artists portfolio should contain as wider scope of their artwork as possible, such as grey, colour, japanese, portraits, cartoon, sketch etc... The portfolio should reflect your diversity as an artist and also showcase your talent and skills.

If you are an artist which doesnt have a portfolio with extensive peices or you are too new to be able to show case a high enough leval of skill then you should include drawings and paintings, or an alternative way to showcase creativity.