Uit een Amerikaanse site:
Add more heat and possibly a gaseous form of sulfur bearing compounds. For example try baking them in a very warm oven (About 200 degrees) and you might try burning a small piece of brown paper in the oven with it (Not directly under it, you want to add the
sulfur compounds to the air in the oven not smother the coin with them.). The trick with the faster methods of toning is the timing. With this method the time between not long enough and too long may be seconds. As a general rule toning speed increases with temperature. It will also increase rapidly with the smoke addition.
One problem with this method is the coin will often take on irridescent colors. Another problem is that often the toning layer is not bonded well to the coin.
Another trick I use is I have a toning brush. This is a #4 goats hair jewlers brush whose bristles have a light coating of Blue Ribbon that has a trace of sulfur ointment in it. Brushing a coin with this brush adds a very thin even layer of very lightly sulfured oil to the coin. This will greatly speed up the toning but still allow it to be stopped easily. Since the toning develops more slowly it tends to hold and look better.Beide methodes gebruiken zwavel. De tweede is niet na te bootsen, want ik krijg geen duidelijkheid over wat "Blue Ribbon" is, maar de eerste ziet er riskant uit. Secondenwerk en ook nog de kans op regenbogen en afspringen. Mss kan ik het toch maar beter houden bij de vensterbankmethode. Langzaam, maar ongevaarlijk.
Peter
