The present disclosure relates to a dyeing composition for human keratinous fibers, such as the hair, comprising, in a suitable dyeing medium, at least one oxidation dye, and at least one dicationic compound. The workstation is based on a computing platform having a graphical user interface, a processor and a computer storage medium containing digitized records pertaining to a patient including image data. The second and third connector ends are connected to the body by a pair of coaxial cables.