It is best to mix professional paint. If you are trying to do it the first time, try to mix colors and apply a single strand. If the result you will be satisfied, then proceed to complete hair coloring.
It should also be borne in mind that the result will depend on the color in which your hair is already colored. If you painted them several times a dark chestnut, then get the color 4-5 shades lighter in one color is unlikely to succeed. It is better to gradually move each time to a lighter shade.
To mix different colors of paint, pick standing close pitch. Only in this case you do not do harm to the hair.
For mixing, prepare a special glass or plastic bowl and brush. Put on gloves. Take two types of paint of one manufacturer. Mix only the same type of paint. Pour the entire contents of the vials or bags and carefully stir. Then directly apply the paint on the hair. Leave it for a few hours is impossible, as the chemical reaction begins immediately upon mixing.
If you think that mixing is necessary to take only part of a darker shade, then after the cook mixture, discard the unused balance, because the store open such dyes is not recommended.
Before carrying out the mixing of two or three kinds of paint, think it may be better to paint the hair one color, and a few strands make the surface of another color. This will remind highlighting, hair will sparkle in the sun shades. In addition, you do not have to experiment with mixing colors.
If you're absolutely set on mixing paints, be sure to check out their composition. In fact in contact with incompatible components on the hair can cause irreparable damage to your hair.