A friend of mine asked me to explain my process a little better. I will probably edit my post about it a bit to clarify some things. The other day we sat down (via google chat) and I explained my usual steps. This is the image to come out of it.
When My children watch me draw they ask how I can colour in an image so quickly without going out of the lines… actually I have a secret. I use the “preserve transparency” option in painter. It means I only have to colour in the lines once. Once I turn it on I can change colours as fast as I want and it wont show up where I have not previously coloured.