For best results to achieve 5D on uncolored hair apply 5D on 5N (Light Chestnut). If 5D is applied on 1N, 2N, 3N, 4N, the color will be very dark golden chestnut - to dark chestnut. On 6N, 7N, 8N, the color will be light golden chestnut to light chestnut. The same rules will apply for 5R, 5M.
5C - the Ash color will be very cold and flat. The Ash color is used to neutralise unwanted gold/red.
To cover grey hair with 5D, it is essential to mix appropriate quantity of 5N - See instructions on leaflet inside the color box or refer to 5N