The process of photo etching on metal has been around since the 19th century. Artists used a mild electric current and copper sulfate solution to etch copper and brass plates. In that era, artists had to carefully paint their pictures onto the metal plates, but today this process is much simpler. When photo etching on metal at home, artists should typically follow a certain set of steps. The metal plate must be carefully cleaned and the photo should be transferred to the plate in a certain way. After that, the artist should take precautions to protect his or her skin from the chemicals necessary to the etching process.
Cleaning the metal plate is one of the first steps for photo etching on metal. The artist should carefully scrub the front of the plate with very fine, soap-free steel wool. When the plate is shiny, it should be clean and can be wiped with a soft, dry cloth. This removes dirt and grime from the plate that might prevent the picture from adhering to it properly. The plate should be handled with rubber gloves after it has been cleaned.
Next, the artist should prepare the picture for photo etching on metal. Pictures with strong lines and lots of contrasting shading often work best. Artists may use a photo manipulation computer program to make these pictures black and white. They should be printed on good-quality photo paper and centered on the metal plate. The artist should then iron the picture onto the plate with a clothing iron set on the cotton setting, without steam. Pressing firmly, the artist should iron the picture this way for about 2 minutes.
Immediately after ironing the picture onto the plate, the artist should soak the entire assembly in warm water. This softens the photo paper so the artist can peel it away, leaving nothing but the ink image behind. The artist may then fill a plastic container with a copper sulfate solution. This solution can usually be found at chemistry or art supply stores. It should be handled with rubber gloves because chemicals used for photo etching on metal may be caustic to skin.
The artist should then clip an alligator clip wire between the metal plate and the positive terminal on a battery containing nine to 16 volts. A second alligator clip wire should be clipped to the negative terminal. The metal plate and the negative wire should then be immersed in the copper sulfate. This creates a circuit that will etch the plate wherever there is printer ink. Every 10 minutes or so the artist should lift the plate from the solution and gently wipe it down with a soft cloth.
After an hour, the artist should disassemble the etching bath and rinse the plate in cool, clean water. He or she should then scrub the plate with very fine sandpaper to give the image definition. Metal polish should add a shiny final touch.