I have a plan - I want my hair to be dark ginger/brown. Kind of like this:
But maybe a little bit more brown. This colour dye DOES NOT EXIST. I've tried various shades of red and reddy-brown but they always have weird dark plum/purple undertones. About 2 months ago I dyed my hair ginger (permanant), then 2 weeks ago put a dark chocolate semi-permenant over the top and it looked gorgeous! But now the chocolate has washed out and I'm back to ginger.
So the plan is... buy 2 permanant dyes - the ginger and the chocolate. Mix HALF of the colourant of each into one bottle of developer, shake, apply... = the colour I'm after? Obviously I'd still have half of each colourant tube left, but surely that's ok because it's not been mixed with the developer yet? It's only the final mixed product that you're not supposed to store, right?
My only worry is that there's different chemicals in the 2 colours that might react badly and make my hair fall out or something. Likely?
No, for several reasons. Firstly different colorants contain different chemicals, some which can react badly together which best case wil ruin the colour and worse case could end in chemical burns and your hair falling out. Unless you know enough about chemicals to understand what might happen with all the things on the box mushed together I wouldnt chance it.
Secondly it probably wouldn't work anyway. I am pretty sure the ginger one will have some kind of lightener in i.e peroxide where as dark brown will likely just be a pigment. I'm no chemical genius but I'm pretty sure the brown is going to have a tough time colouring your follicles while the lightener is trying to strip them.
what i would recommend is not mixing the dyes but using a permanent dye over the top but not leave it in as long as the thing suggests so not let it develop fully...
(if you are more patient than me do a strand test to see how long you need it left on to get the colour you want)
or as someone else said go to an actual hair dresser... they tend to have some way of doing these things...(though that said i am one that avoids this silly money for something that it is possible to do at home some how.... meh nah!)