I've gotten my hair bleached to pretty much a Brienne of Tarth light blonde. I want to get it to the silver in the picture attached. The original post where I found the pic said the gal had used just straight Pravana Silver, so I ordered that and have it on right now. But then I came across this post ( http://www.hairdyeforum.com/index.php?topic=12758.0 ) on the forums here where the gal says she left it on for 6 hours!!! I thought color stopped processing after like an hour or so. Help? I have enough to do another round if need be (my hair is pretty short), but I'd like to know if I'm better off leaving it in for hours and hours instead of the 20 minutes on the instructions (I had just bleached my hair out to very nearly white).
Dyes not working after an hour are oxidative dyes. Pravana is a direct dye. They are just, very basically speaking, like conditioner with lots pigment in it. The longer you leave it on, the more the pigment can attach itself to your hair.
Yes basically the rule is if you mixed it with developer (peroxide) or mixed two or more components to make up the dye then don't leave it on longer than the time it says, if it is a direct dye which is just a pigment such as directions or Manic Panic where they are just in a bottle you apply straight to your hair you can leave it on longer and this will help increase it's staying power in your hair.
Thanks for expanding on that! I meant to add about peroxide but totally forgot *whistle*
Many thanks! I wound up leaving it in for about 6 hours. The color is ok. My ends are really shot so they turned out pretty purple. But I'm headed out to get a cut right now so hopefully that'll even things out a bit.