When using permanent hair color, it is necessary to use a developer to activate the color and help it penetrate the hair shaft. The strength of the developer needed depends on the desired result and the natural depth of the hair. Here are some general guidelines for choosing the right developer:

• For temporary colors or semi-/demi-permanent colors, use weaker developers (3 Vol. to 20 Vol.) or even no developers.
• For permanent colors, use moderate developers, usually 20 Vol. to 30 Vol. .
• For lighteners, use stronger developers, usually 30 Vol. to 40 Vol. .
• Choose a 10-volume developer to lift hair by 1 shade, a 20-volume developer to lift hair by 2 shades and help cover greys, and a 30-volume developer to lift hair 3-4 shades.
• Only use volume 30 hair developer to change your color by 3 to 4 shades, and only on thick or coarse hair, as it can damage thin or fine hair.
• If youre using a permanent hair color, youll need a developer with a higher volume, usually between 20 and 30 Vol. .

It is important to follow the instructions on the hair dye kit and mix the hair dye and developer together in the correct ratio. While any developer should work with most any color line, many color lines formulate a specific developer to best work with their color formula, so it is recommended to use the ideal partner products for best results.