Changing an indicators colour depending on its value . . .

Hi Guys,

I am playing with with my first couple of indicators and have a binary indicator that I am modifying.

I have got it plotting as a histogram, it plots +1for true and -1 for false.

If anyone knows if it is possible to change the color of the histogram bar based on its value could they please post a link of an example, or if there is a command just let me knw what the command is.

Thanks
Steve