Dyeing hair with professional hairdressing colours is often more complicated than dyeing hair with colours from drugstores. For dyeing hair with professional hairdressing colours it is almost always necessary to buy two products, which are:
These two components are usually mixed together before hair dyeing in a specifyed ratio. The resulting mixture is subsequently applied on hair.
The developer is often sold only in a very large package. But some brands sell developers in a small packages for one application (e.g. Wella Professionals or Schwarzkopf Professional). We always recommend to mix every professional hairdressing colour only with a developer which is designed for the colour.
The force/concentration of the developer is expressed in percentage (%) or units Vol. The higher the number is the stronger the developer is and it therefore more lightens hair. Weaker developers or even no developers are used for temporary hair dyeing. Moderate developers are used for permanent hair dyeing tone in tone or for a darker tone. Stronger developers are used for hair lightening or for covering gray hair.
Professional hairdressing colours are often labeled with numbers or combinations of numbers and letters. The first number in these numerical designations denotes the height (saturation) of the colour tone. The higher the number is, the brighter tone is (ie. 2=black, 12=platinum blond). The other numbers or letters indicate reflections of the colour.