Home hair dye products all have very clear and strict timing instructions, generally don’t leave it on for more than 25 minutes, max, if you have stubborn grey. (And my hair is very grey, has been for a long time. Actually that’s not true, it’s silver. Bright, shiny silver. And that would be cool except that it makes my complexion look like death.)
I have a lot of hair, (See my MPSIMS thread for proof…) hairdressers have always commented on the fact that while it’s very fine, I have a large amount of it and it takes a long time to work through it. It’s also very long, halfway down my back. So making sure I get it thoroughly covered with color takes a pretty long time in itself. So obviously the parts of my hair that get the color first have it on for considerably longer than the total time allowed in the instructions if I start timing after I’ve completely covered it all.
So what gives? What’s the true time it can be on my hair without damage? And what would happen if I put it on and fell asleep for 3 hours? Would it all fall out? Something tells me that home hair color is milder than salon and it’s probably pretty safe even if I leave it a long time, but I’d like to know the Straight Dope.