Dutch Metal and Tarnish

 The pleasure of a low price soon fades away when tarnish arrives and the expense of repair is faced. Notice I said "when" tarnish arrives. Oxidation. I used to always believed that if prepped right, handled with care and sealed properly, Dutch Metal (composition metal leaf) would last a very long time before it oxidized. I have since learned that in the making of the leaf, the heat that is required starts it off before it is even handled.
  It is made mainly of copper and zinc. About 85% copper. Copper is going to tarnish. So it is important to make this clear to a client that you cannot guarantee against tarnish and that if this finish is for the long haul, real gold would be cheaper in the long run. The added cost of labor in the future for a re-do would far exceed the initial cost of gold.
  Having said this, to insure you get as long of life as possible if composite leaf is used, remember that oxidation can come from the back side too. It is just as important to have the substrate sealed as it is to seal the leaf upon finish. One should also know, that some products used as your seal/base should be allowed to cure. You may need to wait up to 14 days. Lacquers and paints off gas for a long time till cured and can be part of the problem and also start the tarnishing process.
  Bottom line, explain all possible issues that can happen with Dutch Metal and never guarantee it for life!