No, unless the hair is VERY soiled or has heavy product build-up.
Yes and after.
yess, it is recomended. so all the oil and chemicals in your hair can be washed out and better results
no
yes
No u should always wash it before and after:d
Yes, & you should. Your hair should be really clean, actually, before colouring it. If it is not, the colour will not take as well.
Yes
you can if you want to, but you don't have to.
If you are in the dying process: you just wash it out with shampoo If you are trying to get rid of it: idk, let it fade
It will remain the colour you have dyed it, but dont dry it with a hair dryer afterwards because it will become to hot and the dye will come out.
As long as you wash your hair with shampoo before going to bed than it should not.
You can (and should) bathe and wash your hair when you have a cold. Just make sure you dry your hair completely before going out in cold weather.