It's something to consider when bleaching your black or dark hair is what's underneath.
When you're bleaching black or dark hair to a lighter shade you have to worry or consider the undertones of your hair. One tip is to try to bleach one piece. Try a test strand. What I mean is taking a strand of hair from behind your hair, something easy to camafloge, in case it doesn't come out the color that you like. Apply some bleach or lightener and watch. Check it every 10 minutes and see how light it's getting.
At the end of about 30-40 minutes you should have a good idea on how light your hair is going to go. Now that we have a good idea on how light your hair is willing to go the lightening process is going to take two separate parts. The first is lightening the hair and the second is choosing an all over tone to make the hair the target shade. Once we lighten the hair and we've seen how light it's ready to go we're then ready to choose our target shade. Most of the time the darker hair shades have a lot of warm tones like gold or oranges that are left over still even after the bleaching process. In order to minimize the warm tones we should choose a cool tone or an ashy shade to put all over in order to minimize the gold and the orange and the unwanted brassy tones that come from bleaching dark hair.
Now that we've bleached our hair, we've gotten it to the maximum lightness, we've picked out our target shade, we'll apply our target shade all over our hair and process for 20-30 minutes. It's a good idea to check in and wipe a piece off as you go to make sure it's coming out the color you'd like.