The better the hair to absorb water, the less needs to be added to the peroxide solution. And if your hair is tough - need to increase the concentration of peroxide. Because coarse hair badly moistened with water.
What is the coloring? The fact that the pigment, determining the color of the hair losing its color and becomes colorless on oxidation of oxygen, which is released from the hydrogen peroxide. The more keep concentrate on the hair - the more they are discolored. Only need to know when to stop, and you can grab a chemical burn.
If you have sensitive hair, a high concentration of oxygen hurt them. Here it is necessary to mix in a little solution of ammonia, which will accelerate the reaction. If there is no ammonia - add bicarbonate, ammonium. These alkali contribute copious oxygen from hydrogen peroxide and an outer layer of hair scales open. Oxygen penetrates the hair and coloring pigment. Positively affects the process of clarification by the fact that this generates heat.
With the smelling salts also necessary to be careful, do not add too much. By the way, an overabundance of ammonia can make your hair red. Well, of course, fiery red, but slightly reddish. 50 grams of concentrate enough 5-6 drops.