Basic dye is a stain that is cationic (+ ve charged) and so will react with material that is (-ve) negatively charged. The cytoplasm of all bacterial cells have a slight negative charge when grown in a medium of near neutral pH and will therefore attract and bind with basic dyes. Some examples of basic dyes are crystal violet, safranin, basic fuchsin and methylene blue. It’s applied to wool, silk, cotton and modified acrylic fibres. Usually acetic acid is added to the dyebath to help the take up of the dye onto the fibre. Basic dyes are also used in the coloration of paper.