Silver has a natural affinity with sulfur. Because of the sulfurcontent in our atmosphere, silver gets coloured dark gradually with time.

You can intensify this process artificially with a Liver of Sulfur-bath or Parisian Oxide. If you use it, silver gets dark, nearly black, in a very short time.

Take a brush and paint the Parisian Oxyde over the silverīs surface 6 or 7 times. Then let it dry for 5 minutes. The parisian oxide is most usefull on surfaces with recesses, dents and drilling-wells. After that, you can work on the surface with sandpaper, and the lower parts stay black. Look for pictures on
(tp-gold.com)

You find more information and filmclips about blacking silver in Tutorial No.2 - Just click "HERE"