What would happen if i put bright red hair dye on copper hair?

my hair is dyed a copper/auburn color


i would like to know what would happen if i put a bright red hair dye


like in this pic


http://www.lorealparisusa.com/_us/_en/external/images/products/large/HCo7_41_large.jpgWhat would happen if i put bright red hair dye on copper hair?
It will probably look exactly like whats on the box. But keep in mind that your roots will not be the same color when you touch them up with this dye since that is virgin hair (undyed) and wont be as vibrant.