Hiya,
Just to let you know that Nouvatan's 20% doesn't fully develop after washing it off after say 4 hours for a 12% shade. It continues to develop over the 24 hours. So if someone wanted a 12% shade at 6pm and had their tan done at 2pm, they could wash it off at 6pm but it wouldn't have developed fully. They will probably say they woke up the morning after darker than they went to bed. Just something to bear in mind. For the different %'s of Nouvatans 20, wash off after:
2 hours - 8%
3 hours - 10%
4 hours - 12%
5 hours - 14%
6 hours - 16 %
7 hours - 18%
8 hours - 20%
hope that helps