Coloring your metal with chemical patina.
These chemicals are mild acids and are caustic. They should be treated with respect and safety precautions must be observed. Use appropriate rubber hand protection, safety glasses and something to protect your clothes.
You should do several practice plates to learn how to control the patina reaction. The intensity of color can be controlled to some extent by the intensity of your chemical mixture and the amount of time it is in contact with the leaf. A good place to start is 1/8 teaspoon of dry chemical to 1/4 cup of warm water. ALWAYS had the chemical to the water NEVER add water to chemical!
Potash Sulfurated turns silver leaf a gold tone, then magenta, blue and finally black.
Barium Sulfide turns copper leaf purple.
Sodium Sulfide turns copper leaf orange, then magenta, then blue and finally black. It turns Dutch metal (fake gold) orange, then magenta, then blue green or gold green.
Equal amounts of Cupric Nitrate and Ammonium Chloride turn dutch metal to a green, chalky-bronze patina.
I purchase my supplies from http://www.artchemicals.com/
Examples on this site:
https://woodpops.com/gallery/wood-and-copper-vase-385/
https://woodpops.com/gallery/bronze-and-wood-goblet-384/
https://woodpops.com/gallery/wood-and-copper-rice-bowl-383/
https://woodpops.com/gallery/gilded-temple-box-382/
https://woodpops.com/gallery/oak-and-copper-prayer-box-292/
https://woodpops.com/gallery/poplar-gilded-canister/
https://woodpops.com/gallery/prayer-box/
https://woodpops.com/gallery/oak-and-copper-pitcher/
https://woodpops.com/gallery/greek-pitcher/
https://woodpops.com/gallery/greek-urn/
https://woodpops.com/gallery/turned-bowl-with-copper-leaf-patina/
https://woodpops.com/gallery/lidded-vessel-with-patina/
I learned this technique from David Marks at a workshop sponsored by Woodcraft. Go to David’s web site to see how the professional does it.
http://www.djmarks.com/sculptures.asp
and see his video on youtube
http://www.youtube.com/watch?feature=player_embedded&v=748iRXvvWTE#! .
I highly recommend his CD Video
Guilding and Chemical Patinations with David J. Marks & Grace Baggot avaliable at
http://www.artchemicals.com/Guilding_Patinations_David_J_Marks_Grace_Baggot_p/808131526.htm