Cruella De Vil, Cruella De Vil, if she doesn't scare you no evil thing will! To see her is is to take a sudden chill, Cruella, Cruella De Vil!
2. Now, I'm obviously not sure what your current hair colour is but to achieve the half white and half black look you are going to have to lighten your hair. PLEASE, and I can't stress this enough, don't fry your hair trying to achieve this. It's not worth it and with a little time and patience you will eventually achieve that white colour you so desire.
Bleach: To lighten your hair you're going to want to go to the salon if you're smart, where they can use nice things like Olaplex and not fry your hair, but if you're stubborn like me and insist on doing your own hair, read on! You're going to want a purple based bleach because if we think about colour theory, purple corrects orange which your hair is going to likely have a ton of once bleached, might as well help combat it during the bleaching process. Blue does correct orange, but I've found that it can stain your hair which is not cute and can go green.
Developer: You're going to want a developer to go with your bleach, I carefully use a 40 volume developer because my hair is naturally very dark brown and I can usually take it down many levels with this intense of a developer. The lighter your hair the less intense of a developer you're going to need.
3. Once your hair is bleached it's probably going to look pretty orange/yellow which is fine, don't panic! This is totally normal and all you have to do is tone it, under every orange/yellow hair is a nice colour. If you don't understand why hair goes brassy when bleached, just look at the photo I have provided below. Every hair colour has an undertone to it which is basically all that is left when you bleach your hair.
If you've bleached your hair and it's still not light enough don't bleach it again right away. Deep condition and let it rest for a few days/ however long you feel it needs. You can still tone it because you obviously don't want to be walking around with orange hair if that wasn't your desired look. So for example if you were a #2 and you bleached your hair and it turned a light yellow we can assume that once toned it will actually be a #7/#8 and you can have your hair like that for however long until you want to bleach it again. Once you bleach it again it will need to be toned again for the same reason.
When it comes to toning your hair you totally have options and it depends how you want your hair to look after it's done. Make sure to research your toners so that you do get the desired look you want! In order to get your hair white your hair has to be very light blonde initially so that the toner can take it to white, as seen above. I chose to tone my hair with Wella T18 (originally called White Lady) and it toned my hair to a light silver, not my desired choice, but still lovely.
4. Now for the black colour! This is super simple but you've got to be super careful. I personally opted for a permanent black dye because I do not want to damage my hair any further switching colours after this so I didn't give myself the option to be able to. If you don't want to keep your hair like this for long definitely opt for a semi permanent black because stripping a permanent black is not something I recommend and will definitely not end well. When you're applying the black make sure your light side is completely separated so that it cannot accidentally be dyed. Even get a friend to help you on this part because like I mentioned before the black is very hard to remove and it's a hassle you don't want to go through.
5. When you finally go to wash your hair out wash the two colours separately or else the black is going to run into your blonde and you're going to be really sad that it's become a muddled gray colour. Personally when I wash my hair I take the blonde side and shampoo first off to the left side of my hair and keep it there. I then switch to the black side and make sure to shampoo it and keep it off to the right side. I then wash that out separately and repeat with the conditioner. You'll want to do this the first few times you wash your hair because dye does tend to run for awhile.
When washing your hair make sure to wash it in luke warm to cold water. When you wash your hair in warm to hot water you're opening the hair cuticle which is where the hair dye is sitting and it's going to fade very quickly. If you keep it in cold water the hair cuticle doesn't open as much and your hair will last much longer!
For shampoo and conditioner you're going to want to keep the hair nice and bright by using a purple shampoo, my favourite is Pravana Purple Shampoo and Conditioner. I have seen a ton of people that love the Shimmer Lights purple shampoo too, although I've never tried it. You don't have to use the purple on the black side because it's not going to do anything for it obviously and so you can use another shampoo and conditioner if you choose.
6. Enjoy! So there you have if folks, this is how I achieve my beautiful half and half hair and maintain it! Feel free to watch the video below to see my actually do the steps I have listed above and see the results!