Either ammonia or hydro-sulphuret of ammonia is necessary to color grey hair black ; a strong solntion of galls or sumac may be substituted for the gallic acid. The sulphuret of potassium (in ...

Oksana Klymenko – stock.adobe.com When hair turns gray, it is due to the gradual decline of pigment cells within the hair follicles. The natural color of our hair comes from melanin, a pigment ...