What is Etching?
Etching is a traditional process of using an etchant (strong acid or mordant) to cut into unprotected parts of a metal surface to create a design in intaglio (incised) into the metal. The areas not to be etched are protected with a resist which will not be ‘eaten’ away by the etchant. Great care needs to be taken protecting all sides of the piece not to be etched, including the sides and back of the piece.
The etchant used depends on the metal to be etched. I use Ferric Nitrate as the etchant in my silver etching process. I heat it on a low heat in a non-corrosive container, in a water bath. Once the silver has been prepared and the resist applied, the pieces are lowered into the etchant. My etching set-up usually takes 1-3 hours depending on the temperature of the etchant, and the depth of etch required. The silver is then removed from the etchant, and neutralised. The resist is then removed and the silver is ready to be made into jewellery.
Creating the Resist
Preparation for etching is extremely time consuming, and can take many hours per piece. There are a variety of methods I use dependant on the design and how many I intend to make. These include:
This process is essentially the process of developing an image, using a sticky photo film, onto silver ready to be etched. The film I use is a Dry Film Photopolymer. This is heat laminated onto prepared silver and the image exposed onto the silver.
The image needs to be created as a transparency where the clear elements will create the resist, and the black areas will create exposed areas of metal to be etched. I create the image on my computer and print it on an OHP sheet.
Preparation for photoetching needs to be completed in a dark the room, where the image is exposed over the photofilm covered silver, using a UV light box. The film is then developed, excess removed and light hardened ready for etching. This is a really delicate and time consuming process and I only use this for large batch production pieces.
Nail Stamp Varnish
In this process I use nail art stamping plates and specific nail stamp polish directly onto prepared silver. The stamping plate is covered in polish and, using a rubber stamp, the image is transferred to the silver. This process is relatively fast in comparison to photoetching, but has limitations on size; and is dependant on the images and quality of the stamping plates.
In this process I hand paint the resist onto prepared silver using a number of resists including nail polish, stop out varnish and permanent inks. I only use this process for one-off organic pieces which require a low etching depth.
Traditional Engraving for Etching
I am just learning about this traditional etching process, using Lascaux Hard Resist solution. The solution creates a waxy resist over the entire silver plate. I then hand engrave the areas which are to be etched. This removes the resist so that the engraved areas are exposed ready to be etched.
I am currently testing using a Silhouette machine to engrave computer generated designs into the prepared sheet so as to create more uniform and repeatable designs.