You have many choices to cover your gray. You can use the Ecocolors botanical Haircolor to temporarily turn your grays a nice shade of red. You can use a color like Ecocolors golden blonde to make your grays a nice golden blonde color. This is a permanent haircolor and might slightly change your natural color as well, depending on the color you start with and the porosity of your hair. You could use a color like light brown and focus painting only your gray area, or try it all over. You did not mention your natural color so these are suggestions based on a dark brown hair color. Always do a strand test before applying any new color to your entire head. For resistant grays leave the color on for 35-45 minutes.
