Could someone explain the ketostix for me please?

I got some today and tested (day 5 of induction). The stick showed darker than 4 (moderate) but not quite as dark as 8 - is this enough for the programme and at which of the colours/redings are we considered to be in ketosis?

Thanks very much, and thanks for the answers to my earlier post too. I overdosed with cream cheese today and started to feel a bit sick - it was even worse when I realised that I was supposed to be counting the carbs for it as I took it to be free because it was on the free list of my book!

I'm learning....
Shaz