When lightening hair five or more shades, bleach must first be applied. If hair is being lifted only one to four levels, hair color alone is sufficient.
To color brown hair blonde, the first step is to determine the number of shades lighter the target color is than the natural color. Hairstylists use a system that includes hair swatches and color charts. The amount of lightening determines the level of peroxide used, with 10 percent lifting one shade, 20 percent lifting two shades, 30 percent lifting three shades and 40 percent lifting four shades. Anything more than four shades requires the use of hair bleach to strip the color to the target level of lightness. Usually the hair is then toned to the desired shade.