Hi there. :)
To bring out the blues and purples and greens on sterling - for a peacock look - I use day old LOS -- its weaker, and I mix some ammonia in with it.
The thing to be careful with is to seal it so that it doesn't fade. I'm experimenting with a piece for another group - for fading on a piece I did about a year ago....I'll post the pics here soon as I get a minute - in the meantime - here is some info I posted on my blog the other day:
The Science Company offers a slew of patina formulas with instructions as well as the products needed to achieve the results.
See the "tutorials" here.
Since those are more like directions maybe than true tutorials, here is another method for adding some color to your metal.
Coloring on Metal - The information presented here is taken from many different sources - magazines, ganoksin, forums, and my own general experimentation.
Materials:
- metal
- sandpaper
- colored pencils
- gesso (can be found with paint supplies at most arts and craft stores)
- small artists paintbrush (x2)
- turpentine
- laquer
First your metal should be clean.
It helps if the metal has a bit of 'tooth'. Rubbing it with sandpaper will provide the necessary tooth for the following steps. *NOTE* any soldering should be done prior to coloring.
Apply a thin layer of gesso with a small paintbrush. Allow to dry. (if there are bare spots, apply a second layer and allow to dry)
Begin coloring with pencils - it helps to work in thin layers.
Once a base layer is applied with pencils, apply a thin coat of turpentine with paintbrush. Allow to dry.
Repeat.
The idea is to add thin layers of color and then apply turpentine to slightly blend the pencil into itself.
When you have achieved the desired depth of color seal with laquer. Spray laquers are easy to use and should be applied in THIN layers. Allowing each layer to thoroughly dry before applying the next layer.
For some examples of coloring on metal see the following artists:
Deb Karash
Deborah Weld (scroll down to "show me the color series")