How to dye hair
I am that girl with short pink hair. You can trust me, I promise. If nothing else, my experimentation -- I've gone from blue to cherry red to an unfortunate foray with black -- can save you from making the same mistakes. If you're interested in dyeing your hair unnatural colors, there are a few things you can do so nothing goes awry.
If you have light hair (platinum to dirty blonde), you're in luck -- unless you want white hair or the most vivid color chemically possible, you can skip the bleaching. But if you're like me and have dark hair, bleaching is essential. Get a friend to do it. It's a bitch to get the bleach all the way to the roots when you can't see half of your head. Follow the instructions on the box. Generally, you mix some toner with some powder, brush it on your hair, wait about 30 minutes then scrub it out. It sounds counter intuitive, since the bleach is really harsh, but don't use conditioner. That comes later. For now, you need your hair as stripped as possible so it can suck all the dye up. Do not, under any circumstances, try to store your unused bleach. It will explode.
If you've already got a friend handy, you might as well get them to do the dyeing, too. A lot of dyes tell you to only apply to half an inch from the scalp, but given that my hair is about two inches long, I said screw it and dyed to the roots. Your scalp might get a little discolored, but you'll live. If you're using quality dye, though, it will stain like mad, and that includes your towel, your clothes, your pillow, your skin ... everything. Put Vaseline at the edge of your hairline to protect your skin from staining. Use an old towel. After you've got the dye in, blow dry your hair on one of the low heat settings for about three to five minutes, then let it sit for two hours.
When time is up, rinse, don't wash, the dye out, until the water runs clear. This may take a while. Use conditioner and rinse again. Bleaching zaps your hair, so be sure to condition frequently. My hair has fared well, but a friend of mine told me about her bleached hair just snapping off.
Even if you do all the right steps, the process can still fail miserably if you use a bad dye. Despite hearing others extol the many virtues of Manic Panic, I'm not a fan -- the darker colors may be fine, the cupcake pink that my hair is supposed to be is pretty pale and often mistaken for blonde. I've heard good things about Special Effects, sometimes available at Hot Topic and readily accessible via the internet, and I'm using it to re-dye the pink. We'll see how it goes. Bottom line, do your research and find what's worked or failed for others.
Good luck. I really enjoy having pink hair, and I hope anyone who puts this advice to use will like their new color, too. Just remember: With strange hair, you are easily memorable and instantly recognizable. Your professor will know when you skip lecture.