Question about light reflection.

I have all white walls in my grow room and I read abunch of stuff that said that white walls are good for reflecting light, so if you don't have white walls you should put up some white papers all around your grow spot. But I have seen a lot of you more experienced growers in here use all these reflectors that come with their lights or they buy seperate and then put up all around their plants, I have been wanting to put up Aluminum Foil on all the walls around my plants to help them get more light. But I only thought about it after I already had my grow room put together, and rather then try and move them all out and put the Foil up, I waited until now when I found which were male/female. So, I have 1 female now (THANK GOD!!!!) and I just want to know if it will help to put the Foil up today when I fix my set up? ~ JRock.

P.S. PLEASE HELP!!!!