How Long To Leave Vitamin C On Hair
I am trying to get as much color out my hair as I can right now. I have an odd patchy darkness to some areas of my color, and I think it's from over saturation. But I'm not really sure, since this is a first. It almost looks like my hair's brassy, but before my last dye refresh I had no issues.
I already did one vitamin C treatment, which worked great on the blue, but barely touched the pink or purple. 
I am going to do another today/tomorrow using more vitamin C, and some dandruff shampoo I grabbed for $1. How long do you all leave your treatment in? I'm finding answers ranging from 20 minutes to an hour, but wanted to ask all of your opinions, since so many of you use this method. I want to get as much out of these fading treatments as I can. Thanks!
I have left it in for 20 minutes and up to an hour and it seemed like when I left it in longer it didn't make a whole lot of difference. What seemed to make the biggest difference was how much I worked it through my hair, same with other fading treatments. I usually try to really work it through and lather it/squeeze out excess/reapply more for the first 15 minutes, then I put a bag or something over it and let it soak in for about a half hour, that's what works best for me anyway.
I also tried this, which took out a ton of color: http://haircrazy.info/forum/products-and-techniques/8948/ You don't have to use peroxide in it, though it seemed to take out a lot more when I did use it.
It looks like you have a diagonal shaped spot that is slightly darker in your purple and I can see it in the pink as well. Like it's still more yellow or ginger. I would do what you've been doing, try to fade it all out as much as you can, then spot bleach bath that part. I recommend fading it first because if you were to apply the bleach right now on the purple especially, you'd probably end up with a bright mid to light toned green. If you can fade it first, the most you will get is a pastel which you can easily cover with the purple you have
Always clarify and demineralize your last cleansing before any chemical process to avoid adverse results or unstable chemical reactions! Remember that test strands can save you a world of headache, that protein damage is permanent, moisture is essential, you can use coconut oil as a lightener pre treatment to minimize protein reduction, and that Olaplex can reform broken disulfide bonds so long as they haven't already negatively paired, but it does not address protein or moisture.
How Long To Leave Vitamin C On Hair
Source: https://www.haircrazy.com/forum/dyeing/9653/how-long-do-you-leave-on-vitamin-c-treatment/
