With the tough economy, I want to start coloring my hair at home.  My husband is willing to do it for me!  I'm however afraid to mess up my hair.  This is what I'm working with -- my hairstylist uses Goldwell Topchic on my roots.  She also runs a different Goldwell product on the rest of the hair, but she doesn't put this on right away.  The timing is different each time she does it and it seems she just keeps it on as long as she needs to depending on whether she is working on another customer.  So I can't determine the processing time. 

 

I've determined she uses 7N or 7NN and 7P or 7NP.  She did take down the 7NG or 7NP canister, but I"m not sure she put any of that in. 

 

My problem is that my hair gets very brassy in between colorings and my hair has always pulled a lot of red tones.  

 

So my questions are:

 

-- What's the different between 7N and 7NN and 7P or 7NP?

-- Should I skip adding any 7NG if my hair tends to pull in the brassy tones?

 

--What would the product be that she pulls through the ends?

 

--What is the general timing of both products?  I can't seem to find this info on the internet.  I'm guessing this info is available at my local beauty supply store, but I'd like to be armed with some info before I get there so I don't feel overwhelmed with decisions once I get there.

 

-- What volume of developer should I use?  My hair is probably at least 50% gray, however I"m guessing at this because I can't see the back of my head.  Before I started having her coloring my hair, I had a hard time covering my gray at home and she said it was resistant.  She used to pre-treat it but hasn't done that in a long time.  She now uses a formula that's for resistant hair, but I'm not sure if she just changed the developer. 

 

Thanks in advance if you can help with any of the above questions.  I truly don't want to mess my hair up and most important, I don't want to have to go back to her for COLOR CORRECTION.