The positive grain story...
If you look closely at the diagram, you will see that the surface area around the positive grain 'bump' is larger than the surface area the 'negative grain' hole. If you take any surface, a bump naturally becomes a hole by turning that surface upside down. It's definitely a chicken and egg story. What we (are trying!) to say is that on a positive grain surface, the volume between the bumps is large enough to prevent the accumulation of dirt and hence the holds will keep their 'rough' surface for a long time. If there is a simple and clear way of saying (or showing) just that, we would welcome the input!
Maud Girard
Altissimo Concept