Black Friday - how did it become black?

Always wondered why the Friday after the U.S. thanksgiving holiday is called Black Friday?

Well I wondered that too!  Most common answer I have gotten was from people saying it is because the sky is still black when shoppers flock to stores hoping to be the first few to get in and get advantage of deals.

According to this BBC news article, it is called Black Friday because it is the day most stores hope to get out of debt (usually numbers in debt is red, positive amounts are in black).  So literally the Friday after Thanksgiving is the day Americans help retailers get out of their debt.  

This makes me wonder, should they change it to Black Wednesday?  This way the retailers can give thanks to the consumers on Thursday?