Bleaching

Bleach can only lighten hair color.

It cannot put color into the hair, and is usually it is the first part of a two step process. The second being to do an all-over color once the natual red/orange tones have been bleached out.

Bleaching can be done as an all-over bleach or as bleach highlights.

Of course bleaching the hair is a bit more damaging than regular hair color. However, when red tones are unwanted, the results are best when bleaching.

The need to apply a second color and allowing enough time for that to process, makes proper scheduling very important. If you have dark hair and want a blonde or light brown, non-red color, you need to bleach & tone.