Health and Beauty Coloration L'Oréal Professionnel Dialight Ammonia-Free Color 50 ml 4 Acid technology for sensitized hair.A tone-on-tone coloring without ammonia and without odor to personalize the color of the hair (medium and long). What does? Helps to obtain perfect reflections with infinite shine. It can also be applied to natural hair to give bright and luminous reflections as a shine bath. How does it act? It revives the hair color and can create new shades on top of the main color. How to use: Step 1 For its application, mix a tube of Dia light color with Diactivateur. Step 2 mix until you get a homogeneous creamy texture that is quite unctuous. Step 3 Apply to roots and lengths, if necessary. Step 4 Exposure time for 20 minutes.