How to Darken Jewelry With Acid

Antiquing metal jewelry darkens and colors the metals giving depth and elegance.

A natural or chemically created film of color that forms on metals, specifically copper, silver and bronze, characterizes a patina. Many people value metal jewelry that has a naturally darkened patina because it implies the piece is older and possibly an antique. Jewelers can design new jewelry with a variety of patinas ranging in color from blues, greens and red to gray and black. Several acids are used to create the colors desired and liver of sulphur is employed to darken silver.

Things You'll Need

• Small bowls
• Household ammonia
• White vinegar
• Sealable plastic containers
• Sawdust
• Organic dried tobacco
• Table salt
• Small cooking pot
• Liver of sulphur
• Jewelry buffing cloth
• Jewelry tumbler (optional)
• Tweezers or needle nose pliers
• Soft cloth

Instructions

Blue Patina on Copper

1. Clean the copper thoroughly with soap and water to remove oils or film. Allow it to dry.

2. Fill a small bowl with 2 to 4 ounces of ammonia and set to the side.

3. Place the copper piece on a saucer and dampen with an acid such as white, household vinegar.

4. Set the copper piece and the bowl of ammonia in an airtight plastic container.

5. Allow the copper to cure for several days. Check the color changes occasionally until it reaches the desired color.

6. Remove the copper item from the container and wash gently in water.

Green-blue Patina on Copper

1. Place either sawdust or untreated, dried tobacco in a sealable plastic container.

2. Mix a solution containing one-part vinegar to three parts of house ammonia.

3. Add just enough of the vinegar and ammonia solution to lightly dampen the sawdust or tobacco.

4. Make a pickling solution to clean the copper by pouring vinegar into a small pot. Heat the vinegar and add table salt until the mixture is saturated. Do not boil the solution.

5. Clean your copper jewelry piece by soaking in the pickling solution until it is clear of all surface grime. Remove it from the solution and rinse in cool water. Pickling removes color, grime and oils from the surface of the copper.

6. Place the clean copper piece into the mixture of ammonia and either sawdust or tobacco, covering it completely with the mix. Seal the plastic container and allow the jewelry to remain in the mixture for at least an hour or up to several days until the desired color is achieved.

7. Remove the jewelry from the sawdust mixture and rinse clean.

Black Patina on Silver

1. Place a small lump of liver of sulphur -- the size of the tip of your little finger-- into a cup of hot tap water and allow it to dissolve.

2. Stir with a stainless steel spoon to blend.

3. Heat the piece of jewelry first under hot tap water and then dip it into the liver of sulphur solution. Use tweezers or needle-nose pliers to hold the jewelry.

4. Immerse the jewelry completely in the liver of sulphur solution and hold it there for several seconds.

5. Remove it and rinse in cool water. Check the color. Liver of sulphur works very quickly to oxidize, or darken silver.

6. Repeat the oxidizing process to continue adding layers of darkening to the jewelry until it reaches the desired blackness.

7. Allow the piece to dry and polish with a soft polishing cloth or a tumbler to remove portions of the blackening and reveal the depth and beauty of the piece.

Tips & Warnings

• Raw tobacco is available from health food stores. The tobacco you use to color the copper should be organic to ensure its purity.

• Liver of sulphur is available at jewelry supply stores.

• Oxidize silver wire before you cut it to save time.

• Practice polishing after blackening silver. If you remove too much patina, you can always repeat the steps and darken the silver again in the liver of sulphur.

• Wear gloves when you are working with acids or oxidizing metals.

• Avoid getting liver of sulphur on your hands or inhaling the fumes.

References

• The Jewelry Sweet Spot: How to Oxidize Silver and Copper Jewelry with Liver of Sulpher
• Jewelry Lessons: Creating Color on Metal -- Patinas
• Lapidary Journal Jewelry Artist: Cool Tools