Howdy... this is an area I would be very ignorant of, so just as a matter of pure interest to me I`ll keep an eye on any replies you receive. I`m curious to know what colour is your hair ? I wear `1b` and have never done anything except apply a layer of Knot-sealer when the system is delivered. Is it the case that the hair is a light colour, and the knots are dark ? Thanks, Paul.