Firstly, accept that your hair will need bleach. I’d say bleach it about 2 shades lighter than your hair colour, and no more unless going white. Why? Because you have to deal with upkeep and regrowth – if you lighten it any more, it will only take 2 weeks before your hair is obviously in need of dyeing, and dyeing that often is bad for it and completely unnecessary.
If your hair is naturally black, or you don’t take the above advice, consider dyeing patches instead of the whole head – e.g. the middle section in a band from above your ear to just below it, or dyeing your hair a tamer colour all over, then dyeing patches of extreme colour over the top in big sections.
Try to choose colour based on the assumption it will be about two shades darker than it looks in tube. Yes, your hair will lighten to the colour it appears in-tube, but it will do so unevenly and by the time that happens, it’ll need a re-dye. You will need about 1/4 of a tube left over, so if you have a lot of hair, you may need more tubes than initially assumed.
Bleach can be any blonde hair dye. For your extreme dye, I’d recommend one of:
Fudge – my favourite, especially because if you get rained on in town the colour doesn’t run all over your clothes! But their red selection is a bit crap, in my opinion. Also, Fudge doesn’t fade too badly and I’ve used it years at a time with no unpleasantness.
Directions – Stay out of the rain. Really wicked colours and probably best looking if you really keep on top of upkeep. But after 8 months or so of use, the colour didn’t hold well anymore, so I personally won’t touch it. Also, this one will rub off on clothes/bedding.
Special Effects – I’d say avoid rain, but it isn’t too bad. Can be pretty cruel to anything the dye touches in terms of removal. Colours are pretty cool. Fades pretty heavily the first week or so, which can be a pain if you really thought through your colour and got it ‘just right’.
If you have an inside day or can wear a big hat, start the process. You need at least 6hrs with colour dye in your hair. This is a long time. Consider covering your bed in towels and letting it dye overnight.
1. Bleach hair. Look at shade. Accept your hair colour will not be magically lighter than this shade!
2. Moisturise with an especially oily moisturiser around your hairline, over ears, down back of neck.
3. Apply dye. If doing more than one colour, think through your order of dyeing. I do it all at once, but can only get away with this because I don’t do dissimilar colours.
4. Put hair in a comfortable position and wrap with gladwrap, leave about an hour, then after this unless sleeping you can usually comb and style hair, wipe off excess barrier cream and go about a day which doesn’t involve people touching your hair.
5. After a good 6+ hrs, shower and wash it all out- the water may never run completely clear but make sure as much residue as possible is out of your hair.
Upkeep
Don’t wash your hair daily, it’s so bad for it. Try weekly, or every 3-4 days.
When washing hair, use as cool water as you can stand.
When showering and not washing hair, wear a shower cap. This makes an enormous difference.
Add dye to your conditioner bottle. Somewhere between a quarter and a fifth of your conditioner should be dye.
Use leave-in conditioner or do similar lovely things to your hair so it stays healthy.
Look at the back of your head to determine if your hair is fading too much, not the front, as the back/sides fade much faster.
Redye every 3-5 weeks. You should be good enough at looking after your hair because of regrowth, not because of colour fade.
Treat different colour sections separately in everything you do to avoid muddying colours.
Once you know how to do it, it’s easy. It’s just learning how to make small changes.