I’ve been dying my hair for a little over five years, it’s been every shade of red imaginable, blue, and various chunks of purple, pink, fuschia and blue at different times.
The colors I’ve used have all been Raw Color hair dye, which doesn’t have a website apparently, but you can get it at any Hot Topic. The blue I used was Peek-A-Blue. On bleached hair, it’s a pretty vibrant solid royal blue. I used it most recently over a light brown (dyed light brown, that might make a difference) and it came out like in these pictures. The lighting wasn’t good and the camera was crappy, but it’s pretty dark, solid, but glowy blue. So if you want something brighter, I’d definitely bleach first. The Raw Color stuff is great, it’s a goppy kind of gel/cream, you just put it on and distribute it through your hair, let it sit 15-20 minutes (I usually do 20, though it says 15 on the bottle), and rinse thoroughly. It’s “demi-permanent” which means it lasts anywhere from a couple of weeks, to the point of annoyance, depending on how much it takes to your hair. The blue lasted an abnormally long time for me. Many months later there was still a faint greenish tinge to it. (And this last time I got so fed up that it wouldn’t go away I just dyed black over it. There’s a thread somewhere about me wanting it to grow out faster.) Bonus: It’s completely vegan with no animal products at all, and most of the varieties smell really good. The blue I used - smelled like blueberries. My red smells like cinnamon and “candy pink” smells very strongly like cotton candy.
I stay away from any hair dye that has to be processed with heat – I don’t even own a blow dryer, and I never heat style my hair at all, and I think this has contributed to the continuing shininess and non-brittleness of my hair even after five and a half straight years of dying without a break.
If you want to keep your hair healthy and not brittle/broken/screwed all to hell, then I have one word for you. Conditioner! Good coniditioner, and lots of it. Get one specially formulated for colored hair. Also a for-colored-hair shampoo will help keep it from fading. Slather the conditioner on liberally after you shampoo, and let it sit for at least five minutes, then rinse, but don’t rinse quite all the way… your hair should still feel a little bit slippery. And then rinse in cool water, and if at all possible, let air-dry. Hair dryers are the bane of my existence, even though my hair’s really thick and takes forever to dry, if I used a hair dryer it would be frizzy and awful and humongous. If you need more conditioning, I suggest a Vitamin E serum (I use something called [I think] InstantHairRepair. It’s a transparent purple goo in a squeeze bottle, they have it at Wal-Mart), which you put on while your hair is wet, comb through and leave in. It’s been a god-send to me. Conditioner is a hair-dyer’s best friend.