Wella Koleston Perfect Creme Developer - is the only color developer for all Koleston Perfect shades. Specially formulated to work together, perfect colour results can only be achieved when Koleston Perfect is developed with Wella Koleston Perfect. Now Wella Koleston Perfect is even better. Only the HDC Activator in Wella Koleston Perfect can develop the full potential of the HDC Molecules in Koleston Perfect. The stabilizing HDC Activator also deactivates metallic ions, such as copper, that can impair the colour result. Used together, this High Density Colour (HDC) System creates optimum long-lasting colour results with balance, tone and shine.