Black is for Past. 
The past is books we have already read, letters we have already written and the lessons we have already learned.

 

White is for the Present. 
The present is the light we are leaving in. It's pure and clear, here and now and... Enjoy the moment! 

 

Colors are for the Future. 
The future is our dreams, our hopes, our inspirations. It's bright and colorful... Look forward to it!