How can I change the BackColor of a button control dynamically?

I need to have the BackColor of a button to change each time that it is clicked.  I tried to use the C# code of: Button12.BackColor = "red";  But, this caused an error that stated: Cannot implicitly convert type ‘string’ to ‘System.Drawing.Color’.  So, how do I specify the color, either by name or value, of what the background should be?
 Maurice