That is called Martingale betting. Google it for a mathematical proof why it is wrong. Basically you BR needs to be able to withstand x amounts of unfavourable situations in a row, eg black. If you lose that x times in a row, you bust and lose your whole roll. You will actually lose money quicker in the long run by using this system than regular betting.

Edit : http://www.okthen.com/martingale/ <-- read