Hello! Thanks for the compliment :) It’s rare I ever visit this site anymore. So that was a nice surprise!

Let me first start off by advising you to go to a hair dresser.
White hair isn’t something you can achieve out of a normal hair dye bottle as there isn’t actually a dye that can make white hair. If you understand what I mean?

Up until this year I had been going to a hair dressers to get my hair done for around five years, I had the same hair dresser every time and he was a friend of mine :)

I can tell you what I have done at the hairdressers? And hopefully that will help you. I can also advise you on what I use on my hair now instead of going to a salon, but as I’ve said I would recommend you go to a hair dresser and go through the motions as there isn’t really a quick way to achieve white hair.

So at the hair dressers I would have a full head of bleach. Although this is just for my roots as I have had white hair for so long. For you, as you have darker hair, you’d need a full head of bleach and some times hairdressers will just refuse to bleach your hair or will make you go through foils one step at a time which can take months and months.

So the full head of bleach (I can normally stand up to an hour - I have medium ash blonde hair naturally so it takes very quickly and because of my hair condition it can with-stand a LONG time with bleach) again this will be based on your personal preference of hair type, how quickly the colour will take and how long a hair dresser would risk leaving bleach on your hair.

After this the bleach is washed out of my hair and then washed with silver shampoo. I have always used and would highly recommend Loreal Silver Shampoo. It is so pigmented it can even stain my hands after using it. It will keep the hair a blue/purple silver tone and eliminate any yellow tones in the hair. (Just a note, I have to use this EVERY time I wash my hair because of how white mine is, how often you use it will also depend on the colour you already have or want to achieve).

Then I have to bleach tone my hair, which is the most important part. Any lilac toner should do the trick but my hair dresser always used Loreal Luo Colour P02, and I always use this on my hair now I do it myself as well. This is mixed with liquid bleach peroxide and put over my whole head so the roots aren’t the only white part of my hair.

After that it’s pretty much just keep it up with the Silver Shampoo until you need your roots doing again.
Like I said, I had mine done professionally for years and I would recommend searching around for a good price and a hairdresser willing to bleach your hair for so long.

Now I can tell you the products I use personally on my own hair now, but I wouldn’t recommend doing it yourself at home.

I use B Blonde by Jerome Russell Bleach Powder and any Bleach Peroxide (the liquid) at 40% Vol, you can buy large bottles in most hair stores, if not Jerome Russell also do small bottles. (I wouldn’t recommend using 40% first time, and your hair dresser probably wouldn’t either) I only bleach my roots as I already have white bleached hair. I normally leave this for around 40 minutes, you might need longer for dark hair or shorter if your hair can’t take it.
I then use the Loreal Luo Colour toner mixed with some of the liquid peroxide bleach and put that all over my head and leave it for as long as I can. This WILL make your hair look bright purple at first when it is on your head, after you wash it off it’s more of a baby lilac tinge. But the more purple in there, the less yellow so the brighter purple you let it go before washing it off - the better!
After that it’s just silver shampoo when I wash my hair, and a normal conditioner.

I hope this helped.
But do go to see a hair dresser first at least to get some advice, or even do a strip test to see if your hair actually will bleach up :)
I’m sorry this was so long winded. I’ve actually answered this question before and that was a long answer too.
I don’t want to fob you off with a silly answer, so I hope I’ve been detailed enough! If you have any questions or anything let me know :)
I’d be more than happy to give you advice!
All the things I’ve mentioned you can buy from either Amazon, Boots or Superdrug :) 

Thanks :)